Momentum Men's 1M-DV72U0 Aquamatic II Two-Tone Steel Bracelet Watch Quality automatic movement; functions without a battery; powers automatically with the movement of your arm Mineral crystal Case diameter: 39.4 mm 316-l-stainless-steel-and-18k-gold case; blue-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