Omega gents seamaster planet ocean watchfeatures chronometer date helium escape valve screw in crown transparent case back unidirectional rotating bezeldata crystal domed scratch resistant sapphire crystal with anti reflective treatment on both sides case steel dial black water resistance 600 m 2000 feetmovement caliber omega 8500 self winding movement with co axial escapement for greater precision stability and durability free sprung balance 2 barrels mounted in series autom