"Citizen takes the dive watch to the next level. Whether you need a 1000 meter dive watch with helium release for submersibles and other professional applications, or just want to be cool and the envy of your diving friends - this is it Features include: Solid titanium case - stronger and 1/3 lighter than steel Enhanced water resistant construction to withstand depths up to 1000 meters Helium escape valve protects the watch when ascending from deep depths One-Way Rotating Elapsed-Time Bezel - Bezel ring easily detaches for cleaning Screw-Down Crown at 9 o'clock position allows for easier wrist movement Rugged pressure vented rubber strap fits over wetsuits or street clothes - an extender is included in the kit for extra length when needed 6mm thick sapphire crystal is virtually scratch-proof Automatic self-winding movement winds from the motion of your wrist and requires no battery This massive watch measures approx. 47mm (1 5/8 inches) without crown, 54mm (2 1/8 inches with crown) and is 18mm (approx. 3/4"" deep). Five Year Citizen Warranty"