Once the case is sealed, the watch is ready for its water resistance inspection. The process is in three parts.
First, the watch is tested to ensure that no air can enter. Each watch is tested individually in a pressure tube.
The watch is then immersed in water and pressure is applied to check that there is no water leakage.
The watch is then heated and a drop of water is placed on the glass. When the inspector has verified that no condensation has occurred, full water resistance is assured.