Omega Men&#39;s 3552.59.00 Speedmaster Racing Automatic Chronometer Chronograph Watch Quality Swiss Automatic movement; Functions without a battery; Powers automatically with the movement of your arm Scratch-resistant sapphire crystal with anti-reflective treatment inside Case diameter: 42 mm Stainless-steel case; Black dial; Date function; Chronograph functions; Tachymeter function Water resistant to 330 feet (100 M): suitable for snorkeling, as well as swimming, but not diving