Omega Speedmaster 38 Co-Axial Chronograph Watch - 38 mm Steel Case - Mother-Of-Pearl Diamond Dial - 324.30.38.50.55.00138 mm stainless steel case, bezel which includes a tachymeter scale on a white ceramic ring, scratch resistant sapphire crystal anti reflective treatment on both sides, white mother of pearl dial includes horizontal oval subdials which are diamond trimmed 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 reserve, stainless steel