c.1887 Keystone Watch Co. Patent “Dust Proof” Watch – 18-Size, Gilt-Damaskeened Plates, 10 Jewels, ETP ~7,400. In addition to Abraham Bitner’s Patent Micrometric Regulator, this watch features many other patents issued to Bitner during his leadership at the Keystone factory.
The prominent “Dust-Proof” feature was accomplished with a windowed attachment covering the balance wheel – essentially “sealing” the mechanics of the watch from outside debris.
This watch is correctly fitted with “Keystone” shape gilt hands and is housed in a gold-filled case manufactured at the Essex Watch Case Company using the “Standard” name and trademark.
In the late 1880s, the Atkinson Bros. company sold these as complete watches via various schemes, including the formation of watch clubs in major cities across the United States.