Keystone Watch Case Co. Case Trademark
![[Keystone Logo]
Warranted
18K
U.S. Assay (Keystone Watch Case Co.)](/assets/images/media/Trademark-KeystoneWatchCaseCo-20.jpg)
Trademark Manufacturer:
Keystone Watch Case Co.Manufacturer Years Active:
1880 - 1956Trademark Markings:
[Keystone Logo]Warranted
18K
U.S. Assay
Traits:
14K GoldSolid Gold
Warranted
18K
U.S. Assay
Solid Gold