Omega Men's 4500.50.00 De Ville Prestige Automatic Chronometer Watch Quality Swiss Automatic movement; Functions without a battery; Powers automatically with the movement of your arm Scratch-resistant sapphire crystal Case diameter: 34.7 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