Omega Speedmaster Moonphase Master Chronometer Chronograph Watch - 44.25 mm Steel Case - Yellow Gold Bezel - Grey Diamond Dial - Grey Leather Strap - 304.23.44.52.06.00144. 25 mm stainless steel case with anti magnetic properties, transparent back, 18K yellow gold crown and push pieces, 18K yellow gold bezel with green ceramic ring and Ceragold tachymeter scale, scratch resistant sapphire crystal with anti reflective treatment on both sides, grey sun brushed dial with diamond polished 18K yellow gold indexes and hands, caliber 9904 self winding Co Axial master chronometer movement with chronograph and moonphase