The MK17 EVO 2/S600 features a NEWLY designed sealed diaphragm first stage and an air-balanced second stage with years of proven performance under its belt. The MK17 EVO 2 is more compact and lighter weight than its MK17 EVO predecessor and the MK19 EVO with a NEW forged body, dry chamber with a twin spring layout for increased reliability and compactness. The S600, with its rugged reinforced technopolymer casing and stainless steel front face and ring, provides a steady, effortless flow of air, regardless of depth or water temperature, in the most demanding dive conditions.