AWS Gemini-20 Milligram Scale 20g x 0.001g–Digital Jewelry/Lab Scale for Powder, Gold, Gems – Includes Calibration Weights, Tweezers & Tray–Tare, Cal, 6 Units (Gemini - 20 - Silver)

A great bargain for a cheap scale. It will perform reasonably well if used carefully. Do not expect it to compete in accuracy or durability against laboratory scales, such as those by Mettler or Sartorius selling for $5-10K. This is a nice little scale with a 4 by 4 inch footprint, about 1-1/2 inch tall, including the clear and colorless hinged draft shield. It fits into a neat magnetic-latch box. Batteries are included, two 10g reference weights, and cheap tweezers. The weighing pan is non-magnetic stainless steel. I have two of these scales to save trips to the weighing room. The first one has been in use for 6 months with no problems. The scale is not quite ready to use as delivered. First, the weighing pan has adhesive residue. It is that sticky gum that can only be removed effectively with citrus oil or a citrus oil cleaner, such as Goo Gone. Second, and as others have noted, the pan sits too low on the scale body, and often touches the body of the scale during weighing. This, of course, will not work. The remedy is to glue a 10 mm diameter by about 0.5 mm thick non-magnetic metal washer to the underside of the pan. See my photograph at top of the Amazon listing. Although this will reduce the weighing capacity of the scale by the weight of the washer, it is insignificant. The washer I used weighed about 530 mg. Third, the tweezers are crude. If you have any serious weighing to do, you really should buy some quality tweezers with about tip #2. Dumont (Swiss) and others make good stuff. Of course, a single quality tweezer can easily cost more than this scale. You can economize by buying their epoxy coated electronic tweezers. NOW, REAL TESTING. How accurate? How precise? To test, I used a set of laboratory reference weights, and an older Mettler Toledo AG204 DeltaRange scale in the lab. This is an expensive machine (about $5-10K depending on features) that measures to 0.1 mg. First off, on the Mettler, the two 10 g AWS calibration weights weighed in at 9.9991 g and 10.0001 g. Not bad; they were within a milligram. How about precision? Took a 1000 mg lab reference weight and weighed it on the AWS ten times, with a complete on/off/tare between each weighing and a closed draft hood, in mg: 999, 1003,1001, 1001, 1000, 1000, 998, 998, 1000, 998. Not too bad. Variation of 5 mg. Perhaps with careful placement, a solid surface, and a quiet environment, this variation could be reduced. How about accuracy? Here are side-by-side measurements of reference weights on the Mettler and the AWS. The scales were not tared each time. Just put the weight on the pan. The AWS was not calibrated first trial, calibrated on the second trial. Accuracy could surely be improved with taring, stable environment, etc. Calibration weights, in mg - Mettler - uncalibrated AWS (calibrated AWS) 5 - 5.0 - 5 (5) 10 - 10.0 - 10 (10) 20 - 20.0 - 19 (19) 50 - 50.0 - 48 (50) 100 - 100.0 - 100 (100) 200 - 200.1 - 200 (199) 500 - 499.8 - 501 (499) 1000 - 1000.3 - 1001 (999) 2000 - 2000.0 - 2001 (2000) 5000 - 5000.2 - 5005 (5000) 10000 - 9999.6 - 10011 (9999) 20000 - 20000.0 - 20022 (20002) Again, this is impressive. With calibration, the measurements were off by no more than a milligram or two. My recommendation is that if you need an inexpensive scale to measure within a few milligrams, and are willing to calibrate manually, buy this scale. If you must have absolute accuracy, set aside at least $10-20K on a laboratory scale, stand, and accessories, and dedicated weighing room. And if you need real accuracy, get an equal-arm balance. Update 30 May 2012 These two scales have been in use for over a year. Still perform well. They have been repeatedly tested. The measurements continue to be at least as accurate and precise as given above. Measurements have been published in peer-reviewed scientific journals. Depending on the project needs, and with reference weights and quality scales to verify performance, you can use this scale for scientific research. And remember, when you are weighing to the milligram and below, even the best scale will perform poorly with bad technique. This is not some yard-dog scale at a metal recycling plant. Have a clean, stable environment. Eliminate vibration and movement. Place the scale on a stable bench (if possible, granite is used in labs). You should be sitting, not standing. Arms off the bench. Eliminate air currents. No magnets. Keep magnetic steels away. Do not breathe directly on the scale. Use the draft shield. Gently place the object to be weighed on the pan. Don't drop it onto the pan. Don't use your fingers. Do not place the object directly on the pan. Use weighing paper or a disposable pan. After placing it on the pan and closing the draft shield, wait 10 seconds or so, for the scale to settle, before recording the weight. If you would like a fuller explanation of good weighing technique, Mettler has an excellent pdf user guide, "Weighing the right way," on their website. Update 4 Sept 2012 Some mention should be made of the pan. It is not the usual flat pan, but rather a dish with a spout. It gives the unfortunate impression that one can load a powder or some such in the dish and then pour it out. Not standard practice. For my use the pan is fine, but others should consider a substitute "pan" out of non-magnetic metal or even cardboard with a washer spacer below. The subject powder or object should be placed on weighing paper or weighing cup. Be sure that there is enough room to close the draft hood, because without the draft hood closed, all milligram and sub-milligram scales are unreliable. Update 9 Sept 2012 For those who have not worked in a lab, some mention should be made, after reading reviews on this scale, just what can be expected from any milligram or submilligram scale, whether it costs $25 or several thousand dollars. At this measurement level, subtle influences can greatly affect measurement. You cannot just throw a sample on the pan and hope for the best. Unfortunately, you need to know what follows. First off, these are scales, not balances. Balances compare a known, measured, mass against an unknown mass. They operate correctly anywhere there is gravity, no matter what the variation, even on the moon. In contrast, the AWS scale and even many expensive laboratory scales measure the force that gravity and centrifugal force of the earth's rotation exerts on a mass. Because gravitational force and centrifugal force vary slightly with the position of the scale on the earth, all these scales need to be calibrated after installation. Expensive scales do this automatically. With cheap scales, such as the AWS, you do this with a calibration weight. Unfortunately, the AWS calibration weight is too big, so you cannot close the draft shield when calibrating. Bad design. Use an inverted small beaker or such as a draft shield. Beyond that, there are several other significant sources of error affecting all scales: 1. Drafts. All drafts cause severe variation in recorded weight. Keep away from windows, doors, HVAC outlets, radiators, etc. Use the draft shield. 2. Vibration and movement. This will cause erratic readings and visible drift. Even absent outside movements, expensive scales take several seconds to settle down. 3. Temperature. Expensive scales measure and compensate for temperature, Cheap scales do not. If you have access to a set of milligram reference weights, you can check for this. 4. Humidity. Not too high, not too low. 5. Light. Light causes heat, which changes the measurement. Keep out of sunlight and bright artificial lights. 6. Leveling. Expensive scales have levels. Cheap scales do not. 7. Sample position on pan. Always place sample in the middle of the pan. 8. Electrostatic charge. A common and severe problem with low humidity and non-conductive weighing vessels, such as glass and plastic. Increase the humidity or change the weighting vessel. 9. Temperature gradients. Differences in pan, weighing vessel, and sample temperature causes severe problems because of convection air currents. 10. Magnetism. Obviously, any magnetic attraction between sample and something else will cause problems. Several materials commonly thought of as non-magnetic are somewhat magnetic. 11. Buoyancy. Because of the sample size, the AWS scale should not be affected much by this, unless one is weighing a large, low-density sample, which would be buoyed by air. 12. Oil and dirt. A common problem with beginners. Don't touch the pan or reference weights with fingers; use a tool, such as forceps or tweezers. Use weighing paper or some sort of weighing vessel on top of the pan. Generally, do not place a sample directly on the pan. If you make a mess, Windex is the usual cleaner for scales. So, for those reviews that claim without qualification that the AWS is accurate down to a milligram, it would take a lot of convincing. On the other hand, for those reviews that claim complete unreliability, assuming the item is not defective, it may just be one of the many inherent weighing problems. Still, a remarkable scale for the price.

Works very good . Have checked it against other high end scales and it is spot on . The point I like is that there is little if any drift . Only have used it for 4 or 5 powder charges for reloading and it has worked great from 410 to 12 gauge loads . Nice little scale . Very easy to read, set up, and use also .

*********WHY I PURCHASED THIS SCALE*********** I purchased this scale so I could weight out various Nootropics supplements down to double digit MG. Here is a breakdown of what I needed to weigh and how much of each. I filled #00 gelcaps, for the most part, with the following, using the scale to weigh: 12.5MG of Tianeptine Sodium 300MG Adrafinil Powder 400MG Panax Ginseng Leaf Extract (42+% Gensenosides) 600MG Green Tea Extract (50% EGCG, 98% Polyphenols, PE) 1000MG Choline L-Bitartrate 600MG Phenibut HCL These are all part of the current Nootropics stack I'm trying, and in particular, I was unable to weigh out anything under 1g accurately with the scale I had. So, I purchased this scale to accurately weight 1mg - 1000mg accurately. ***********PERFORMANCE AND QUALITY************** This scale comes with 2 x 10g weights, which are both needed to calibrate the scale. My scale arrived perfectly calibrated, so this was unnecessary. However, at some point I will definitely need to calibrate it since all scales require service at some point, so having the price instruments needed to calibrate is very nice. The scale also came with a nice metal tray for weighing small powders, salts, and supplements out. I found it very convenient. Residue has a tendency to stick to it, but that not the tray's fault. The scan performed with STELLAR accuracy. I opened a couple preweighed gelcaps with ~20-200mg and was able to get an accurate reading down to the mg ever time. It was always spot on. Always make sure you scan is on a perfectly LEVEL, FLAT SURFACE. I can't stress this enough. At first my readings were slightly off, even though the scan was on a flat desk that should have been level. Come to find out the floor was off a couple degrees. When relocating to another surface that was flat AND level (on a level floor) I go consistent, perfect readings. *************Conclusion**************** Overall, I'm extremely happy with this scale. I was a bit upset because I selected Saturday delivery, when ordering it on a friday (I needed it ASAP. When the mail came on Saturday and their was no package, I went back to look at the order and the fee for saturday delivery was no where to be found. This is the second time Amazon ignored the fact that saturday delivery was selected (and both times my total had the $8.99 added which I placed the order, and both times the confirmation email had free shipping selected.......) I did, however, receive it the following monday, which is the next business day. The fact that the scale comes with 2 x 10g weights for calibration, a metal tray for weighing powders, as well as some nice tweezers, I think it's well worth the price. I'm very happy and feel I go exactly what I ordered. ####******######******Please vote if this review was helpful!!!!! Thanks and have a wonderful day!!!!*******#########*******########

The Gemini-20 is a great scale for the price. I think they have made improvements to it, because I didn't have some of the problems that I read about in other reviews. I didn't have any problems with interference between the measuring surface and the tray. The tray did not have any adhesive or stickiness on it, and I didn't have packing particles on the reference weight. So I didn't experience a lot of the negative comments I saw in some of the reviews. The scale is great for what I am using it for, which is measuring ingredients for making electrolyte drinks. For that, I need to measure quantities in the 300 - 4,000 mg range, and they don't have to be exact, so variations of +- 10mg are not a problem. The scale is consistent: when weighing the same item several times, I get the same weight within +- 10 mg, even between power cycles. I also get the same results when I put it in a different location on the table. The consistency makes it easy to use: just pull it out and start measuring. I leave it on the default "g" mode, so I just need to press "on" and "tare". The measurements settle quickly, I can make back to back measurements easily. The build quality is what you would expect from an inexpensive scale, but it is well made. Everything is plastic except the measuring surface and the tray. One thing that hasn't changed is that the reference weight is too large and doesn't let you calibrate with the cover down. Not sure why they didn't think of that, but it isn't really a problem for me. If you needed, I am sure you could find a smaller set of weights. For what I need this scale for, it is awesome. I would highly recommend it.

This is a balance but since the title uses the word scale I will call it a scale for simplicity. [Skip to bottom for pros/cons/short version]. This scale is exceedingly well made *for the price* (and reasonably well made even compared to much higher priced ones). It comes in an excellent little protective case that holds the scale and the accessories tightly in place and closes securely with a magnetic latch that is far easier to open than if it were a standard box. The screen is backlit blue with black text and is easily readable in all lighting conditions, the text is large and sharp, and though smaller the mode indicators are also easily readable. The buttons are easy to press and give a distinct tactile click. The lid of the scale opens and closes easily without contacting the weigh boat or changing the tare, it can also be left in the half open position shown which gets it out of the way and is not heavy enough to tip the scale. Included is the scale, TWO 10 gram calibration masses, a measuring bowl and a pair of sharp smooth tip tweezers all contained securely in a carrying case. I would say that this scale is ideal for measuring within the range of 15 milligrams all the way up to 19 grams with a repeatable measuring accuracy of +/- 1.5 mg in the 10 mg to 500 mg range and an accuracy of +/- 3 mg in the 500mg to 19 gram range - these numbers are based on my own testing using professional calibration weights and comparing readings between this scale and a Mettler-Toledo balance in my lab that costs orders of magnitudes more than this little guy. It has mode selections to measure in: Grams Carats Penny Weight - dwt (used in gold measurements, 18.23 dwt = 1 Ounce or avoirdupois) Grains - gn (some pharmaceuticals still use this measurement, aspirin for instance) Ounces - oz (Don't mix this up with troy ounces, which it also measures) Troy Ounce - ozt (Troy ounce, used when measuring precious metals it is equal to 31 grams instead of 28 like a normal ounce) The accessories are of okay quality and the calibration masses check out to within 0.00025 grams of 10g and each other - there is a place for one of the check weights on the scale itself and one in the carrying case which is a little silly. The masses I received seemed to be solid metal, unlike some of the other reviews have said. The weigh boat has a relatively small flat portion on the bottom and the handle is also quite small, this makes it hard to handle and easy to spill especially if you are using it to handle liquid. I personally replaced it with a higher walled teflon weigh boat with a fully flat bottom. The tweezers are tweezers, not much to say there - they are stainless steel with a sharp tip allowing small amounts of sample to be scooped but since they are stainless powder sticks to them pretty significantly, so for my uses I replaced them with a teflon tipped pair of the same size. The only real downside to the operation of this scale that I have encountered is the Auto-Off function, which can no be adjusted, is often much too short - especially if you are closing the lid. For instance if you put your weigh boat down and tare it then remove it to add some sample the scale will often turn off before you have the chance to put the sample back on - this is true even if you dont remove the weight boat after taring and are adding a very small amount of powder, since you must be careful and take your time it will occasionally turn off on you; this can also happen if you're getting really close to a specific amount (say 100mg) and just need to add 2mg more so you just tap your tweezers to add tiny bits of powder, if the amount you add is a bit under 1mg and doesn't cause the reading to change it will shut off on you. I would estimate the auto off to be about 30 seconds. What I do as a work around is remove the weigh boat after taring and tap the scale surface gently every little bit to keep it active, you can also hit the mode button, etc. ******* A QUICK WORD OF WARNING: DO NOT ATTEMPT TO USE THIS BALANCE TO MEASURE OUT 1mg of a something if being off by 1 or 2 mg could be dangerous, just don't do it with this device. Instead measure out 100mg then dissolve in solution. Despite the quite excellent accuracy of this scale over its whole range it simply is NOT the tool you need to measure out a 1 mg sample. I would suggest trying to measure at least 10mg of a sample if you are measuring by difference (i.e. you put X mg on the scale, tare it, then remove sample until you reach -10mg) and >30mg for normal measures. This is a great scale for its price but it is not a scale I would bet my life on measuring out 1 mg, period. Take the extra time to volumetrically divide a larger sample by solution or buy a .00015 gram range balance if that is your intended use. ******** Pros: Scale is far better than I could have ever expected for this price. It is accurate, precise, and the readings are repeatable over a wide range. It includes all needed accessories, the case is excellent and holds everything firmly in place. The calibration weights are accurate (some reviewers said theirs were not solid but mine were). Great selection of modes available, just be careful not to mix up oz and ozt. Highly readable screen. Cons: Included weigh boat is small (even for a small scale like this) and is prone to tipping. The auto-off feature turns the scale off too quickly, especially if you are using the lid to eliminate breeze, requiring you to press a button or something to keep it on and not risk losing your tare. The tweezers are especially prone to static cling when using them for powder measures, the weigh boat is as well to a lesser extent.

I ordered this scale to weigh capsules from a compounding pharmacy. My suspicion was that the drug-to-filler ratio was varying widely. Since one ingredient weighs more than the other, if some capsules in the batch weighed a lot more than others did, there was a good chance I was getting an inconsistent mix of filler to drug. When the scale arrived I followed the calibration instructions (easy-peasy!) and then started weighing the capsules. Yup--big difference. So I took the scale in it's sturdy box and some capsules down to the pharmacy. The pharmacist viewed me with an expression of polite and slightly condescending patience, an "all right, I'll watch--then I'll show you that your cheap little toy doesn't weigh correctly" look. I weighed some capsules and he wrote down the numbers, then took the capsules into the back room to weigh them on his very expensive and accurate scale. When he returned, his look had changed to stunned interest. He asked where I got the scale and how much I had paid for it. He said he was going to recommend it to his customers, who had asked him where they could get an affordable and accurate scale. Yeah, the little round weighing platform is small, but it will accommodate a small pill very well. I didn't have any troubles with the little dish as one person claimed they did-I bet they didn't point the dish's pointed spout towards the calibration weight. That makes a difference! This scale is the REAL DEAL, and does the job. Just read all the instructions and follow them step-by-step. TIPS FOR ACCURACY-- 0) Read the 4 star rating for additional good tips. 1) Calibrate often, as this is a delicate instrument. Calibration is pushing a button and adding 2 weights (included). 2) If you are weighing a capsule or powder to use the little dish (included). 3) Be sure to point the spout on the dish directly at the calibration weight which is stored in a little holder on top of the scale. This scale is VERY sensitive, so if the dish always sits the same way, it will weigh the same each time. 4) When weighing capsules, point one end towards the same stored calibration weight also. That way your capsules and dish will always be in the same position, giving you more "sameness" when weighing things. 5) Always put the scale and accessories (extra calibration weight--you need both to calibrate but one stores on the scale and one in the box--and long tweezers) in the box when done with them. This scale probably won't survive banging around or being dropped on the floor, so put the box where it won't get knocked off a shelf.

For info: I bought this scale to measure powder for reloading rifle cartridges. So, if you want the scale for something else, a lot of these gripes won't apply to you. There is a lot of fail packed into this cute little device: 1. The little holding pan included with the unit does not properly fit into the recessed weighing platform. More specifically, it touches the sides of the housing if you don't place it perfectly on the weighing surface - just a tiny bit off-center, or tilted, will result in incorrect readings. I tried picking up and replacing the pan with exactly the same amount of powder about 15 times and got significantly different results every time (> 50% deviation). 2. The pan is too flat to hold powder effectively. Trying to get powder from your powder measure into the pan *will* result in a granule covered workbench. Every time. Because of #1 and #2 above I had to find a different container in which to place the powder for weighing. But, trying to find something that would properly fit in the recess, and balance on the weighing surface (which has ridges on the outside), and have sides to properly hold powder, was an 'fun filled' exercise. I finally found plastic glue bottle cap. 3. The accuracy is questionable at higher loads. I compared the accuracy of my initial loads (19-24 grains of powder) to that of my RCBS balance scale and it was perfect. But when charging to loads in the 42-47 grain range this thing was off by .7-1 grains (again, compared to the RCBS balance scale). I trust the RCBS scale. 4. The auto-off feature is designed to make a prostate exam seem like a fun event by comparison. By 'fun' I mean watching puppies being set on fire type of fun. In other words, it is really awful. My workflow is: - Place measure of powder in container, - Weigh powder (and correct weight if needed), - Place powder in cartridge, - Insert and seat bullet, - repeat... Upon conclusion of this workflow I am often *just* in time to see this absurd little troll switch itself off. I had to add 'switch unit on, wait to power up, recalibrate' to my workflow. Yay. 5. There is a gap between the recessed weighing platform and the body of the scale. I strongly suspect that this gap is to reloading powder granules what the Bermuda Triangle is to unsuspecting boats -> a mysterious force that lures them in never to be seen again. Seriously, if you mess any powder near the scale, chances are some of the granules will find their way onto the weighing platform (which, being recessed, is an almost certainty), and any attempts to get the granules out will result in the powder finding its way into the internals of the unit (because of the gap). It's not all doom and gloom though, there is a plus side, the box it comes in is really cool.

I'm happy with this scale for the amount I paid. It does have a couple of problems but still I feel I got good value for my money. My main complaint is that the little platform that the pan sits on was tilted. That meant that the pan always had a bad tilt to it and always in danger of contacting the frame, and making the measurement useless. I carefully removed the brushed aluminum sheet (it's glued on) that surrounds the pan, to provide access to the insides. I carefully (VERY CAREFULLY!) bent the little platform so that the pan now sits level on it. After that I re-calibrated the scale and it works fine. I probably should have returned and exchanged the scale instead of modifying it, but I had a feeling that the next one would probably have had a similar problem. Also, I wanted to see what the mechanism looked like. My second complaint is that the scale times out and shuts off while I'm using it. This of course is good for saving battery power. If your intention is to place an item on the scale and find out its weight, then the scale stays on plenty long enough. But for my particular use, the shutoff feature is an annoyance. I want to add a powder a few mg's at a time using a tiny scoop until I have the exact right amount. But the scale wasn't designed to accommodate this, and I keep bumping into the timeout. If I had the exact right size scoop then I could maybe add the powder fast enough to finish before the timeout. I bought some scoops, but they're not measuring out the right amount, so now I have to hunt for a different set of scoops. I'm trying to measure down around 10mg or so, and it appears that getting the right scoops for this job is difficult. So I have to still work on figuring out a technique to be able to make my measurements successfully. But the scale was designed to do a certain job, and it does that job very nicely for the amount it cost. You have the reference weights that come with the scale to calibrate it, and so you can do some pretty good work with it.

Es justo lo que buscaba para pesar gemas pequeñas y conocer cuántos kilates pesan hasta 3 decimales de precisión. Anteriormente compré otras básculas de precios mucho más económicos pero nunca me sirvieron, aprendí mi lección de que es mejor invertir en algo bueno. No se descalibra seguido, pero es recomendable siempre corroborar con una de las pesas de 10 gramos que trae antes de usarla. Trae unas pinzas y un platito para usarlo en modo Tare, en fin, muy recomendable para quienes buscan calidad y excelente precisión.

High precision and easy to use.

Good milligram scale

Leugens, niet Americans maar made in China. Rommel, onnauwkeurig, onbruikbaar.

I have used this daily for about a year now, it's a great scale, and repeats accurately down to within a couple of milligrams. You have to be careful calibrating it, and have it on a solid low vibration surface when you turn it on or zero it. I used a metal file to file about 20mg away from the dish (just a tiny corner of the handle), so it weighs exactly 2.700 grams. I leave it in place when I turn the scale on, then take it off to check the calibration, which reads -2.700. The variation is always within +/- 2mg. It always reads between 2.698 and 2.702. It usually reads within +/- 1mg. It is only worse if I'm shaking the table while it turns on. That is more than accurate enough to weigh anything down to the 10mg range accurately enough to get reliable doses (EG noopept at 30mg dose). There is one thing they did that bugs me, but it's a universal practice on all scales. They make anything within about +/- 6mg read zero. They do this because novice users would be confused why the scale might read +/- 2mg, even though they just hit the zero button. There is ALWAYS a little bit of "jitter", that is just the cold hard truth. But they hide it by displaying 0.000 instead. This means when you want to weigh very small amounts, the scale will not start moving from 0.000 until you get over 6mg on it, and then it jumps to the right number. Don't worry, it's reading true. This is also the reason I always start with my 2.700 gram dish when powering on. I lift the dish, and actually see the true number, like -2.701, and then I know the scale is really properly zeroed with the dish back on.