Citizen Men's BL5500-58E Octavia Perpetual Signature Eco-Drive Multi-Function Chronograph Watch Eco-drive is fueled by light so it never needs a battery Stainless steel silver tone with black ion plated stainless steel and carbon fiber and black dial Multi-function chronograph with perpetual calendar Anti-reflective sapphire crystal Water resistant to 330 feet (100 M): suitable for snorkeling, as well as swimming, but not diving