VTF Vintage Glass Pocket Watch Crystal 21-1/16 (~47.5mm) - NOS

VTF Vintage Glass Pocket Watch Crystal size 21-1/16 = ~46.5mm with a thickness of ~1.15mm. This a Lentille profile crystal that provides a higher dome than concave.  While still likely 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.