The Keystone Watch Case Co.

If You Wear a Watch In a Factory or Shop

you should have a Jas. Boss Stiffened Gold Case in order to protect the works and lessen the cost of repairs. The Boss Case is made of two layers of solid gold with a layer of stiffening metal between. It is better than a solid gold case because it is stronger and so close-fitting as to keep out gas, smoke, dust and dampness.

JAS. BOSS Watch Cases Stiffened GOLD

are recognized as the standard the world over, and sold as such by jewelers. The Boss is the only stiffened case in use long enough to prove by actual wear that they will outlast the 25-year guarantee. There is none "just as good." The Keystone trademark here shown is stamped in each Boss case. 

Consult the jeweler. Write us for booklet.

THE KEYSTONE WATCH CASE CO., Philadelaphia.