OMEGA chronograph Speedmaster Professional Mark III, self winding, Switzerland around 1973, reference 176.002, solid stainless steel case including original bracelet, screwed down case back with sea horse logo, contrast dial, 60-minutes & 12-hour-counter, permanent second & 24 hour display at 9, tachometer graduation, movement gold-plated, 22 jewels, central rotor, calibre 1040, flat rim balance, flat hairspring, incablock shock-absorber, diameter approx. 41 mm, length approx. 18,5 cm, condition 2-3, literature 'Omega Reise durch die Zeit' written by Marco Richon page 609