Omega Planet Ocean 600M Co-Axial Master Chronometer Watch - 39.5 mm Steel Case - Unidirectional Black Cermaic Bezel - Black Dial - Black Leather Strap - 215.33.40.20.01.00139. 5 mm stainless steel case with helium escape valve, transparent screw in back, screw in crown, unidirectional rotating black cermaic bezel with Liquidmetal diving scale, domed scratch resistant sapphire crystal with anti reflective treatment on both sides, black 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, black