Teaming SCUBAPRO’s best-selling second stage with its environmentally sealed first stage creates a reliable air delivery system for all diving conditions. The MK17 EVO is completely sealed off from the elements, ensuring trouble-free operation no matter how cold or murky the water gets. It is more compact yet delivers better breathing performance than its predecessor. Its improved internal design allows more airflow from the LP ports which have been reconfigured for better hose routing. The S600, with its rugged fiberglass rugged fiberglass reinforced nylon casing and stainless steel front face front face, provides a steady, effortless flow of air, regardless of depth.