Vintage Glass Pocket Watch Crystal 21-2/16 (~47.7mm) - NOS

Vintage Glass Pocket Watch Crystal size 21-2/16 = ~47.7mm with a thickness of ~1.65mm which is pretty thick. Typical Mi-Concave Pocket Watch profile and the thickness would suggest it's for a very old Open Face watch case. While likely well over 100 years old, in my 40 years of experience with them I've not found the older crystals to be any more or less brittle than anything you could find today. That said, they are quite likely dirty and need serious cleaning.  I have a supply of crystals that numbers in the hundreds of thousands so I can usually supply just about any size Watch Crystal you need (glass or acrylic) so feel free to inquire. Images do an adequate job of representing the item.