All is not what it seems with watch water resistance, you will not find a watch that claims to be waterproof. This is because no watch can be guaranteed totally waterproof.
The different levels of water resistance as expressed in meters is only academic. They refer to the depth at which a watch will keep out the water if both watch and the water are static. So for example if you have a water resistant watch and you dive into a swimming pool the pressure on the watch at the point of impact with the water will be many times greater then if you were just placing the watch into the water.
A gasket or O ring is used to make a watch water resistant these can be made of rubber ,nylon or Teflon and form a water tight seal at all the joints including the crown (the winding stem), case and where the crystal glass meets the watch case. Another aspect of water resistance is the back of the watch, a screw on back is far superior to a push on back.
The depth that a watch can be ... More information,please visit>>http://www.watchesgg.com/vacheron-constantin/