Omega Planet Ocean 600M Co-Axial Master Chronometer Watch - 39.5 mm Steel Case - Unidirectional White Cermaic Bezel - White Dial - White Leather Strap - 215.33.40.20.04.00139. 5 mm stainless steel case with helium escape valve, transparent screw in back, screw in crown, unidirectional rotating white cermaic bezel with Ceragold diving scale, domed scratch resistant sapphire crystal with anti reflective treatment on both sides, white dial with Arabic numerals and a date window at the 3 oclock, caliber 8800 self winding Co Axial chronometer movement with date function, approximately 55 hours of power reserve, white leather