Antique Hamilton Watch Co. Genuine Factory “Salesman / Display” Case. Size 12S. New Old Stock (NOS) Perfect Condition. Approx. 50mm (2) Overall Diameter. Fits 12-Size Movements (40mm Inner Lip). Complete with Crystals, Stem & Bow. Hamilton Watch Company (Lancaster, PA). Salesman / Factory Display Case (Double Glass). 12S (12 Size American Pocket Watch Movements). 1.566 inches / 39.79mm. 2 inches / 50mm (excluding crown/stem). Case Inner Seat Opening. Bright, smooth nickel base metal. Authentic “Hamilton” script stamped on the interior lip of both bezels. Dual snap-on bezels (front & back) with clean, sharp action. Front & back clear glass crystals, crown/winder, integrated stem, and bow. Historical Significance & Era. Estimated Period of Production: Circa 1905 – 1930. To market these intricate high-grade mechanisms (such as the popular 12S dress pocket watch movements) without risking environmental damage, these official double-glass utility cases were issued. Traveling salesmen and retail horologists relied on these snap-on display cases to showcase the magnificent damaskeening, fine finishing, and mechanical motion directly to prospective buyers. They kept the delicate gears immune to dust and fingertips without forcing the jeweler to repeatedly screw and unscrew retail precious metal cases. Because they were strictly high-utility commercial tools meant for trade representatives, finding a pristine example stamped “Hamilton” in completely unused condition is an extraordinary find. Pristine New Old Stock (NOS): This case is an absolute time capsule. It has never permanently housed a watch movement and remains free from any standard wear, scuffs, or polishing degradation. The crown, bow, and stem are flawlessly aligned and functional. Any orders flagged as using these secondary address fulfillment services are subject to immediate cancellation. We never use stock photos or digitally alter our graphics. Securely packaged and insured for premium domestic/international transport. Thank you for viewing this rare horological listing!