Dive watches generally need to have a water resistance of at least 100 meters with 200 meters being the recommended minimum for scuba diving. Dive watches today are now available with water resistance ratings that are much deeper than you are likely to dive at. You will find watches here with ratings as high as 1000 meters for professional scuba diving. Some also feature helium release valves - a one-way pressure relief valve typically consisting of a strong spring, a plug, and a good rubber gasket. The helium valve prevents damage to the watch due to the buildup of helium gas in the watch after extended stays inside the dry pressurized habitats used for commercial diving.