One of the world\'s most iconic timepieces, this OMEGA Speedmaster Moonwatch Chronograph Calibre 321 Men\'s Watch has been apart of all six lunar missions reprising the famous Calibre 321, an important part of the Speedmaster\'s original space history. At A Glance  Presented on a stainless steel bracelet 39.7mm case size, inspired by the same 3rd generation style worn during America\'s first spacewalk in 1965, and 50m water resistance Black step dial featuring familiar Moonwatch hands with chronograph sub dials Polished black ceramic bezel with tachymetric scale in white enamel Transparent case back Scratch resistant sapphire crystal glass with anti-reflective treatment on both sides Powered by the famous OMEGA calibre 321 manual-winding chronograph movement, the calibre worn on the moon Power reserve of 55 hours