A nickel cased open faced keyless lever military pocket watch, Rolex, circa 1920,

细节
A nickel cased open faced keyless lever military pocket watch, Rolex, circa 1920,
white enamel dial with Arabic numerals and subsidiary seconds, blued steel moon hands, 15-jewel nickel finished Cal.548 movement, nickel case with screw back inscribed with the broad arrow mark and B5238, dial, movement and case signed, diameter 50mm.