Vostok Men's Automatic Stainless Steel and Leather Casual Watch, Color:Black (Model: 2432/0525030) Quality automatic movement; functions without a battery; powers automatically with the movement of your arm Mineral crystal Case diameter: 42 mm Stainless-steel case; black dial; date function Water resistant to 99 feet (30 M): withstands rain and splashes of water, but not showering or submersion