Omega Speedmaster Broad Arrow 1957 Chronograph Watch 3551.20.00. Officially certified chronometer automatic self-winding chronograph movement. Caliber 3303. Column wheel mechanism. Rhodium-plated finish. Geneva waves. Stainless steel round case 42 mm in diameter. Fixed stainless steel bezel with tachymetre function. Scratch-resistant sapphire crystal with anti-reflective treatment inside. Off-white dial with luminous blued steel hands and broad arrow indexes. Date window at 6. Small seconds sub-dial, 30-minute recorder and 12-hour recorder. Brushed and polished stainless steel bracelet with deployent clasp. Fits 8.5" wrist.