Omega Seamaster Planet Ocean 600 M Co-Axial Master Chronometer GMT Watch - 43.5 mm Steel Case - Bi-Directional Bezel - Black Ceramic Dial - Black Leather Strap - 215.33.44.22.01.00143. 5 mm stainless steel case with helium escape valve, transparent back, screw in crown, bi directional rotating bezel with polished bi ceramic black and white insert, domed scratch resistant sapphire crystal with anti reflective treatment on both sides, black ceramic dial with Arabic numerals, caliber 8906 Self winding chronometer movement with Co Axial escapement and GMT time zone function, approximately 60 hours of power reserve, black leather