Citizen Eco-Drive Promaster Professional Diver is used for mixed gas diving with its 6mm non-reflective curved crystal, ratcheted elasped-time bezel, screw-back case & screw-down crown, and reinforced urethane band and extender, with a carrying case for the wetsuite strap extension. Crafted in stainless steel with luminious accents , and 300M WR.