Omega Constellation OMEGA Co-Axial Master Chronometer - 39 mm Steel And Sedna Gold Case - Silvery Dial - Brown Leather Strap - 131.23.39.20.02.00139 mm steel and sedna gold case with anti magnetic protection, transparent back, bezel engraved with Roman numerals, domed scratch resistant sapphire crystal with anti reflective treatment on both sides, silk embossed creamy silvery dial with date at 6 oclock, Calibre Omega 8800 self winding co axial master chronometer movement with date, approximately 55 hours of power reserve, brown leather strap. Water resistant to 50 metres (167 feet).