Omega Speedmaster Moonwatch Professional Co-Axial Master Chronometer Men's Watch 310.30.42.50.01.002. This 42mm watch features a stainless steel case and bracelet with a black anodised aluminum bezel ring. The black dial has luminescent hands and hour markers and a chronograph. It is powered by the Omega Caliber 3861 manual winding COSC Master Chronometer certified movement with co-axial escapement and a 50 hour power reserve.