OMEGA "SPEEDMASTER PROFESSIONAL Steel chronograph watch, black 3-counter dial with painted baton hour markers, enameled bezel with tachymeter scale. Screw-down caseback. Mechanical movement, hand-wound, signed and numbered 39180536, caliber 861. Steel bracelet, articulated links with adjustable steel folding clasp, signed. Circa 1975 (dents and chips to glass, general scratches, small enamel chips on bezel insert). Diameter: 42 mm.