SuperNothing
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This is what wikipedia has to say about depth ratings for watches:
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Quote:
The International Organization for Standardization issued a standard for water resistant watches which also prohibits the term waterproof to be used with watches, which many countries have adopted. Water resistance is achieved by the gaskets which form a watertight seal, used in conjunction with a sealant applied on the case to help keep water out. The material of the case must also be tested in order to pass as water resistant.[6] The watches are tested in still water, thus a watch with a 50 meter rating will be water resistant if it is stationary and under 50 meters of still water. For normal use, the ratings must then be translated from the pressure the watch can withstand to take into account the extra pressure generated by motion. Watches are classified by its degree of water resistance, which roughly translates to the following:[7] * 50 meters (1 meter is about 3.3 feet), which means the watch is suitable for swimming * 100 meters; indicating it can be worn snorkeling * 200 meters, suitable for recreational scuba diving * 1,000 meters (roughly three-fifths of a mile). Watches in this last category can endure deep-sea diving. Their gaskets are made of materials that can withstand the helium used in decompression chambers. Some have valves that let the wearer release the helium that has seeped into the watch so the case won't explode as the watch and diver adjust to normal atmospheric conditions, says Peter Purtschert, technical director at Breitling USA. The depth specified on the watch dial represents the results of tests done in the lab, not in the ocean.[8] Some watches use bar instead of meters, which may then be multiplied by 10 to be approximately equal to the rating based on meters. Therefore, a 10 bar watch is equivalent to a 100 meter watch. Some watches are rated in atmospheres (atm), which are roughly equivalent to bar. In the United Kingdom, scuba divers and others often use the word atmosphere (ATM) loosely (the correct term is "ambient pressure") to mean 1 bar (1000 millibars, or 100 000 Pa). |