Eisco Labs Optical Glass Lens, Double Concave, 75mm Diameter, 20cm Focal Length

The glass was cracked when it arrived.

I got my nephew a professionally spun and tuned spinning top for Christmas. These lenses were recommended for use as a base on which to spin the top as the gentle concave shape keeps the top towards the center and the glass surface provides a smooth surface with little friction. Using this as a base he was able to spin his top several times that night for 4 to 5 minutes and it spun so perfectly it would often hardly look like it was even spinning.

Bought this Eisco Optical Glass Lens to help me with my art projects and I am delighted by the quality of the lens. Wondering if there is a holder available for it. Bought two more for friends in my class.

I have numerous precision tops (AKA Pocket tops, Spinning tops) by various makers from 5/8" to 2.1" in diameter. This type of surface is ideal for many styles except for flat-bottom-tops with a shallow clearance for bearings in tops that are greater than 1.2" in the realm of beginning collectors (as made by people like Twisted Tops, Fludunlimited/BW Flud, Charles Symeonides, and Patrick Ober). The concavity tends to interfere with larger tops with that particular diameter/design. For intermediate/advanced top collectors, this lens should be suitable for your use. This lens works well for tops with stainless, ruby, or ceramic genre of bearings. It also even works well with tops that do not have bearings such as the Inception top, Tippe top, Lance Barnett tops (some select tops that don't have bearings), or Franz Tommasi Delrin/Polymer tops. My lens did have a tiny chip on the edge of the lens but since my purposes were not for optical use, I didn't return it. However, it raises the questions of quality control for my experience. Overall, I am quite pleased with the performance of smaller tops with a wide basilar clearance for my tops, especially from makers such as Blake San (Mountain Tops EDC), Steven Robbins Fine Pocket Tops, the Inception top, Symeon Metal Works, the Tippe/Tippie Top, Twisted Tops, Marke Dalpe, and Fludunlimited/BW Flud.

I have no idea what was responsible for the complaints that others have experienced. My lens arrived in what looked to me to be perfect shape in spite of obvious (mis)handling of the package. This lens is a much better base for spinning Forever tops than the one provided at a much higher price by Forever Spin. Unlike the commercial product, the lens not only seems to keep the top spinning longer and more centered, at the end of every spin, at least so far, the Forever Spin Titanium top stays in the lens when it drops. Sometimes the excess energy is depleted by a rocking motion that sounds a bit like a ticking clock and is tres cool. I will soon try my Vorso top in it and see if it just a one top base or a universally great deal.