1, because ordinary watches are sealed to prevent the invasion of sweat and harmful gases, but they are not absolutely anhydrous.
2. At the same time, there will be some inevitable phenomena in the use of the watch: when the needle is fixed every day, the rubber band in the handle or the handle tube will gradually wear out. The surface glass expands when heated and contracts when affected by temperature, which will cause a gap with the watch case; The waterproof apron of the back cover is aged or corroded by sweat, which will reduce the waterproof performance of the waterproof meter.
Therefore, ordinary waterproof watches must not be worn for swimming and bathing. Even when washing clothes, washing dishes and cooking, be careful not to splash water on the instrument, and don't let water vapor enter the instrument, otherwise the parts in the instrument will rust when exposed to water, which will affect the quality of the pointer and even lose its use value.
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Interpretation of 50-meter waterproof watch:
1. Now many consumers have such a misunderstanding: 50-meter waterproof watches can only be waterproof within 50 meters underwater, but not beyond 50 meters. This understanding is wrong, and it is this understanding that has caused many consumers' 50-meter waterproof watches to enter the water when they are far from reaching the depth of 50 meters underwater.
2. The so-called waterproof watch, in fact, is that the watch has a certain degree of waterproof, and the withstand voltage resistance value is not obtained underwater, but is converted from the atmospheric withstand voltage resistance value. This pressure test is static, not to say that the watch can move within 50 meters underwater.
3, 50 meters waterproof, is an enhanced version of daily waterproof, that is, the watch can not only withstand the water droplets spilled by washing hands, washing faces, showering, etc. Take a bath with a watch and scrub with a small amount of cold water. But you can't soak in the water, let alone swim or dive with your watch.
4, 50 meters waterproof watches are basically 50 meters behind. 5 bar, 5 atm, etc. However, it should be noted that all watches can use hot water and steam. If there is a problem, it will damage the movement, and there must be a mark on the watch manual.
5. Moreover, 50m waterproof has a warranty period, which is generally 1-2 years. It's expired, and the waterproof apron needs to be replaced. If it is not replaced, it may get damp due to the aging of the apron.
Baidu encyclopedia-mechanical watch