Keystone Watch Case Co. Case Trademark
![18K
Warranted
U.S. Assay
[Keystone Logo] (Keystone Watch Case Co.)](/assets/images/media/Trademark-KeystoneWatchCaseCo-33.jpg)
Trademark Manufacturer:
Keystone Watch Case Co.Manufacturer Years Active:
1880 - 1956Trademark Markings:
18KWarranted
U.S. Assay
[Keystone Logo]
Traits:
18K GoldSolid Gold
Warranted
U.S. Assay
[Keystone Logo]
Solid Gold