Many watches often have a distinct seal stamped on the back indicating a depth (BAR, ATM, meters or feet), resistant to static pressure for a short time only at the depth indicated. It can range from 30 to 1000 meters, resistant to accidental splashes, to high impact water sports to scuba diving.30 meters / 100 feet / 3 bar: These watches can withstand minor splash moisture, but should not be worn for swimming, diving, bathing or showering. Most people believe that the "water resistant" engraving on the dial means the watch is sealed for swimming, diving, showering, etc. Not true. They should not be used underwater.50 meters / 164 feet / 5 bar: These watches can be used for swimming in shallow water, but not for snorkeling or other water sports.100 meters / 328 feet / 10 bar: These "divers" watches can be used for snorkeling, swimming and other water sports, but not for deep sea diving or scuba diving.200 meters / 66 bar: Suitable for high impact water sports and water diving that does not require helium.300-1000 meters: These are professional divers watches and can be worn for deep water diving.
The water resistance of watches is not permanent. The seals around the crown, crystal and caseback are subject to wear. Every time a watch is opened for maintenance or a battery change, a leak test should be performed and the gaskets should be replaced.Avoid contact with perfumes, spirits or products.