Omega Speedmaster 38 Co-Axial Chronograph Watch - 38 mm Steel And Yellow Gold Case - Dual Diamond Bezel - Silvery Dial - Green Leather Strap - 324.28.38.50.02.00138 mm stainless steel and 18K yellow gold case, dual bezel with a tachymeter scale on a green aluminium ring while the outside is diamond paved, scratch resistant sapphire crystal anti reflective treatment on both sides, opaline silvery dial includes horizontal oval subdials and a vertical oval date window at 6 oclock, tachymeter scale, Caliber Omega 3330 self winding movement with chronograph, chronometer, date, approximately 52 hours of power