Can’t unscrew the helium escape valve.

Ali Haas

Divers who are going below say 140 feet may need to worry about the He. We use helium to speed up the decompression cycle and minimize N2 narcosis. It would not matter with an externally worn watch but I wear mine inside my dry suit. It's not used during the dive but before and after on the surface. Inside the dry suit is often the same gas you are breathing but may be also from a small He only bottle. An automatic He release valve is needed. In the case of several of the newer watches that are advertised as saturation diver watches with newer seals, (He proof somehow) no worries.

Ali