The one built for saturation divers
By Tom Hargreaves, Falmouth, Cornwall ยท
The Sea-Dweller came about in 1967 because commercial divers working with COMEX were spending days in pressurised habitats, and the crystals on their watches kept popping off during decompression. Helium got into the case and had nowhere to go. Rolex fixed that with the helium escape valve. So unlike a lot of watches on this list, the Sea-Dweller's helium valve is there because it was actually needed, by actual divers.
Not by you, though. Or me. Recreational diving stops at 40 metres.
The modern one is 43 mm, 15 mm thick, 22 mm lugs, rated to 1,220 m. 3235 movement, 70 hours, date with a cyclops (which the old ones didn't have, and purists still grumble about it). The Glidelock clasp is there and has the Fliplock extension for a thick wetsuit too.
That's the bit I'd buy it for. A clasp that'll go over a seven mil wetsuit or a drysuit cuff.
Downsides are the thickness and the weight. 15 mm on a 43 mm case is chunky. And the price, $13,200 to $14,000, plus the usual Rolex waiting game.
For a real working diver who wants one watch for the rest of their life, this is a strong shout.