Seiko & Citizen Watch Forum Message Archive

The L shaped gasket serves two purposes.

1.) It can better fit around the parts to provide a superior seal.

2.) It's made out of compound with increased resistance to Helium

The he-gas divers are designed to both minimize and deal with the buildup of helium in the watch. The helium is minimized through the gasketing techniques and then it is dealt with through a design where the watch can take pressure from within and on the outside. IWC designs under a similar philosophy.

I've never seen anything about a permeable retaining ring or a specific design component made to allow a controlled helium escape. Essentially the watch is designed to be able to take the internal pressure (if it does develop) under the assumption that eventually, the helium will escape over time.

There's been much discussion in the past on this and I know there's a post where Tokunaga actually posted some data from field tests with Seikos and other He Gas divers displaying the buildup and release of Helium over multiple dive simulations.

Japanese Watch Enthusiasts: http://www.gmtplusnine.com