• A patented membrane surrounding the inner nose pocket which acts as a barrier and traps any moisture escaping from the diver’s nose involuntarily when breathing through the mouth. the result is that not only is the moisture channeled away from the lenses, thus avoiding the fogging up of them, but it also reduces the need to compensate for pressure. to further improve the anti-fog effect, cressi suggests, the first times that the dive mask is used, to spray some anti-fog solution or to apply some saliva on the inside of the lenses and then to rinse them with water.