As we know, the waterproof function of a watch works mainly rely on the waterproof rubber ring at the place of looking glass, back over, crown and some other places like these. Water-proof watches put auger-type crown to use, so as to reach the corresponding water-proof standard. By different ranks, the water-proof function of a watch usually divides into these categories, such as No Waterproof, Sweat-resistant, Water-resistant, 30 Meters, 50 Meters, Diving Timepieces 100 Meters, 200 Meters, 300 Meters, and so on.
About the waterproof function of a watch, there is a clear rule according to national standards and international standards: Once the watch is marked as water-proof watch, it should stand 2ATM at least, that is to say, the water-proof function can works well within 20 meters underwater. 3ATM means this watch can stand 3ATM, and the rest may be deduced by analogy. The premise of this standard is that the test should be did in the experimental condition, the temperature should be kept between 20 to 25 degrees Celsius, and the watch and water are both motionless. In this condition, if the watch can proof water, then this watch is eligible.
Someone thinks that the waterproof function of his watch can work 100 to 300 meters underwater, so he can go to sauna with his loved watch around his wrist without worry. In fact, it is totally wrong. Because a watch is not an object which is absolutely sealed, that is to say, a water-proof watch maybe could not prevent from water vapor. If water vapor enters into watch, it will speed up the aging of the rubber ring which is used to prevent water. And the performance of this watch will be influenced also.
Which kind of harms will be brought to a watch if water enters into it? As to quartz watches and electronic watches, if there is a large amount of water entering into them, the quartz substrate will be burned away in the short term. If there is a small amount of water entering into them, maybe there is no problem in the short term, but in the long term, the circuit board will be corrupted by water, and perpetual harm to watch will be caused. If there is water in a mechanical watch, the damage varies from the decline in precision to the impracticability of this watch. So no matter how excellent the craft of your watch is and how strong the waterproof standard of your watch is, do not try to take a bath (except the cold shower) or sauna companied by your watch.
PS: If water has already entered into your watch, please send your watch to the repair center as soon as possible.
Common sense about the waterproof function of your watch:
30 Meters: The waterproof function can work in daily life. It can prevent the splashing of the water. You can wash hands and wash face with the watch around your wrist.
50 Meters: It has stronger waterproof function as one of your daily use. It does not matter if it is flashed by a small amount of cold water. But it cannot be soaked into water.
100 Meters: It is a watch which can be used under the condition of snorkeling. We can use this kind of watch in a swimming pool or on the surface of seawater.
Above 200 Meters: It is called dive table. It can be used in the deep under water environment where people need UBA. Which waterproof standard is suitable should depend on the depth to dive to.