Vintage FLAT Glass Pocket Watch Crystal 18-9/16 (~41.9mm) - NOS

Vintage FLAT Glass Pocket Watch Crystal size 18-9/16 = ~41.9mm with a thickness of ~4.4mm which is insanely thick, comes with no manufacturers markings.  Very thick dead flat profile with a steep bevel, typical of what originally came on large vintage pocket watches, specifically those made well before 1900.  Not pristine as there are tiny nicks along the rim but otherwise very nice. Special procedures must be observed to see these installed without introducing flaws. While still 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 very 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.