No I didn't replace any of the O-rings or the gasket they were all in perfect condition. I don't think this one had ever been opened. There is a retaining ring which is visible once the bezel is off which unscrews to reveal a gasket, then you pop the crystal off and there is a movement retaining ring with an o-ring in a groove which faces upwards sealing the crystal from below. That pops out and there is another o-ring which sits in a recess in the case which seal the retaining ring as well. It is a very well put together watch and I would say was the subject of a lot of detailed engineering to get it to its 1,000m rating. I am hugely impressed with this watch even if some think it is an ugly duckling and am glad I took the plunge in buying it.

: Good to know Davy. Were you replacing any gaskets while you we're
: in there? I've never had any of my Super Pros opened up to know
: how the crystal is sealed or locked into place.