Scubapro S600 second stageThe S600, with its rugged fiberglass casing and stainless steel front face and ring, delivers smooth and easy inhalation and exhalation while offering efficient user controls, including a powerful purge, an inhalation effort control knob and Venturi Initiated Vacuum Assist (VIVA) dive pre dive switch. It provides a steady, effortless flow of air, regardless of depth or workload. S600 Second Stage: Metal valve housing (barrel) is able to withstand