OMEGA Speedmaster Chronograph Herrenuhr, Ref. 175.0043/375.0043. OMEGA Speedmaster chronograph mens watch, ref. 175.0043/375.0043. Stainless steel / 18K YG. Automatic movement, cal. 1155. Case no. 53757198. Signs of wear on case and band! Dial with minor patina! Service recommended! Diameter ca. 37mm (measured without crown).