The watch is cased in 316 stainless steel, with a Seiko automatic movement (SIINH 35) beating inside, with the use of a Single Domed Sapphire crystal (the 3rd hardest substance below Diamond) instead of the commonly used Mineral crystal. The Hydra also has a Helium escape value (for use in mix gas diving) and a water-resistance of 2,000 meters. A fantastic amount, given that PADI (The Professional Diving Association) states that a divers watch should offer at least 100 meters of water resistance. Hydra's 2,000 Meters of water resistance is an amazing twenty times standard! The Hydra is for the customer looking for a reliable automatic divers watch with superior depth rating (2,000 meters) and materials. Style-wise, the Hydra takes its nod from watches in the 1970s, resulting in a vintage look with modern components. Lastly, the weight and depth of the Hydra convey a feeling of safety and ruggedness.