Seiko Men's Japanese Automatic Stainless Steel and Rubber Sport Watch, Color:Black (Model: SNZD23) Quality Japanese Automatic movement; Functions without a battery; Powers automatically with the movement of your arm Hardlex crystal Case diameter: 40 mm Stainless-steel case; Black dial; Date-and-day functions Water resistant to 330 feet (100 M): suitable for snorkeling, as well as swimming, but not diving