There are some elements that can provide moisture resistance to watches. The most significant are the gaskets or circles of Teflon, rubber or nylon that create water-proof shutter at the juncture where the crystal-glass, clockwork head and case back make up the watch-case. In case if the watch happens to be a chronograph, then its pusher screws can have gaskets too.
Furthermore, water-tight watch-cases are equipped with a sealant which is utilized as fluid that helps to prevent water ingress.
The cover and thickness of the watch-case can play an important role in evaluating whether this watch is designated for wearing it under the water. The watch-case is to have hard material that would resist the tension and would not be ruined. On the whole, manufacturers confirm that the case should be either of titanium or steel, or steel covered with gold. Sturdy watch-cases of gold can be moisture-resisting if they are enough sizable.
A screw in the case back, on the contrary to that, which pushes in, is instrumental in waterproofing qualities of watches too. A screw in the clockwork head, the element of watches worn by lots of divers, assists in keeping the water out as it can get into the watch-case through the watch-stem hole. When it is threaded down, it creates a water-resisting shutter that is like a seal between a jar and its hood.
Various levels of waterproofing, evaluated in meters, are just abstractive. They concern the depth at which the water won’t get into the watch-case as long as both the water and the watch are absolutely immovable. Certainly, such circumstances can never happen in real life of divers or swimmers. In the real world, the motion of the watch owner’s arm through the water strengthens the tension on the watch considerably; thus, the watch can be worn at the depth pointed by laboratorial testing machineries.
The following utilization recommendations are proposed by lots of manufacturers of watches.
Please remember that we do not advise diving or swimming with your watch.
It is strongly recommended for you not to wear you watertight watch while having a hot shower, tub or sauna. Heavy heat can cause the expansion of metal parts to different extent than the gaskets made of rubber. This causes tiny cracks which can provoke small droplets of water getting into the watch. Abrupt changes of temperature are particularly severe. Try not to get into a cold pool after you wear your watch in hot sauna.
If you wear your watch while diving or swimming in the salt water, try to wash the watch with fresh water. If your watch is equipped with revolving bezel, spin it around several times while washing it. This will keep your watch from salt formation and corrosion of the bezel ring.
Some chemicals can gnaw the gaskets and make them defenceless. Strongly chlorizated water can provoke troubles as it is sprayed with the help of hairsprays and perfumes that can get into the joints of the watch and ruin the gaskets. (They can spoil the watch cover).
The watch-guard made of leather can be watertight too. Usually the straps of leather are simply spoilt by repeated pressure of water. So if you usually wear your watch while diving or swimming, think of obtaining another watch with a metal strap or nylon or rubber diver bracelet.