The DS4 first stage Unique over-balanced, diaphragm design - as the diver descends, the over-balancing feature allows the medium pressure gas in the hose to increase at a rate faster than ambient. This results in superior performance at depth. An environmental dry system keeps water out of the main spring chamber thus preventing ice buildup and keeping silt and contamination out. A work horse with years of tested and proven experience now preferred by the most demanding dive teams.

1st stage ports: 4 x 3/8 UNF and 1 x 7/16 UNF. A work horse with years of tested and proven experience now preferred by the most demanding dive teams.