The first stage DST4 is balanced, equipped with a DS (Dry Sealed) - closure of first stage by outer membrane. 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.
2 HP ports and 4 MP ports on a rotating turret are angled for optimum hose routing.
An environmental dry system keeps water out of the main spring chamber thus preventing ice buildup and keeping silt and contamination out.