Momentum Men's 1M-DV70B0 Aquamatic II Black Dial Steel Bracelet Watch Quality automatic movement; functions without a battery; powers automatically with the movement of your arm Mineral crystal Case diameter: 40.0 mm 316L-stainless-steel case; black-sunray dial; date function Water resistant to 990 feet (300 M):suitable for scuba diving to a depth of 30 meters for up to 2 hours