Eco-Drive Technology allows the watch to charge outdoors or in artificial light so you never have to change a battery! When fully charged it will run for 120 days without additional exposure to light. (120 Day Power Reserve) Perpetual Calendar so you never have to adjust the date 1/20 Second Chronograph, Measures up to 60 Minutes 12/24 Hour Time Mineral Glass Crystal Genuine Black Leather Strap Dual Time Alarm Hardened Bezel 200 Meters Water Resistant (660 ft) Screw-In Case Back