Deepsea is the name of a special watch made in 60s by Rolex able to reach the Mariana Trench to a depth of around 11,000 meters. Nowadays Rolex uses the name Deepsea to produce a new-generation divers' watch engineered for extreme depths.
Deepsea regularly produced
Exceptions of Rolex watches with or without helium valve
There is a particular and extremely rare Seadweller 1665 without helium escape valve (called single red). And there are even some Submariner models with helium escape valve (a bunch of 5513 and all the 5514)