The subject item is best identified as Illinois Watch Co. 'Sterling' 17-Jewel Pocket Watch, c. 1923, Early 1920s Art Deco, Illinois Watch Company, Springfield, Illinois, USA. Springfield's Illinois Watch Company was a titan of American horology, widely respected for producing heavily decorated movements that rivaled Swiss imports. The 'Sterling' model was marketed during the Roaring Twenties as a gentleman's essential technology, promising industrial accuracy in an elegant form. The 14kt gold-tone-filled S.W.C.CO. case paired a durable base-metal core with luxurious gold-tone plating, decorated with intricate Art Deco engine turning. Produced circa 1923, this watch bridges the transition from the bulky railroad standard chronometers to the sleek, status-driven accessories of the Jazz Age.

The market for early 1920s American pocket watches is highly stratified based on mechanical condition and original configuration. Direct sold comparables establish a strict floor of approximately $225 for non-running 'parts' watches or examples with severe case wear. Fully serviced, chronometer-timed examples retailed by horology specialists establish a definitive ceiling of $400 to $575. Without evidence of recent mechanical overhaul, this watch must be evaluated in the 'running but unserviced' lane. A comparable 21-jewel Illinois 'Sterling' sold for $300 on the secondary open market; considering the subject is a slightly lower-tier 17-jewel variant, an auction hammer expectation naturally falls into the $200 to $275 bracket, reserving the upper bounds for examples with pristine enamel dials and zero case 'brassing'.