Longines Grand Prix vintage wristwatch

18kt yellow gold monopusher chronograph, ref. 5211275, double case 40 mm. fixed lugs, enamel dial with Arabic numerals, tachymetric and telemetric scale, mechanical movement with manual winding, caliber 15 by Valjoux 22 GH, complete with strap with metal buckle and archive certificate from Longines, signed case, dial and movement