A gentleman's stainless steel Seamaster 600m 'PloProf' wristwatch, circa 1970. Automatic. 44 mm. Monocoque case, circular blue dial with painted luminous baton numerals, centre sweep seconds and date aperture, rotating bezel. Case, dial and movement signed. Box, the Seamaster 600 Professional model, also called 'PLOPROF' for PLOngeur PROFessional, professional diver, was launched in 1970. The first series was marked simply '600' on the dial, the second series such as this present lot was marked '600m/2000ft'.