This Omega is 43.5 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 strap with rubber lining. Water resistant to 600 m (2000 ft).