Swiss Staybrite stainless steel lever chronograph Circa 1920

Stainless steel chronograph with register and tachometer
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A fine Swiss Staybrite stainless steel chronograph keyless lever dress watch with register and tachometer, circa 1920. Rhodium-plated movement, 23 jewels, straight-line lever escapement, monometallic balance, Breguet balance spring with terminal curve, index regulator. Two-tone silver dial with painted Arabic numerals, outer minute and fifths of a second track with five-second Arabic numerals on a polished reserve, inner tachometer scale, subsidiary dials for the seconds and 30-minute register and original blued steel Breguet hands. Polished and brushed case, inclined stepped bezel, rectangular bow. Case numbered
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Diameter: 50 mm
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Signed:  No name