Powered by light energy - no battery change required. 10-month power reserve once fully charged. Green uni-directional rotating elapsed timing bezel. Green sunray finish dial. Date calendar. LumiBrite hands and markers. Sapphire crystal. Screwdown crown and caseback. Case diameter: 38.5mm Stainless steel case and bracelet. Tri-fold push button release clasp with secure lock and extender. Water-resistant to 200 meters (660 feet), Diver's Watch. Follows ISO standards and is suitable for scuba diving. Caliber V147