More than an excellent mid-range system. This combination offers high performance, reliable ScubaPro technology and value. Optimized thermal exchange, thanks to external fins. Optional routing cap available. S560 Second Stage A lightweight, techno-polymer barrel second stage, the S560 is air balanced with diver adjustable inhalation effort and VIVA. Ensures effortless and smooth breathing in all conditions. Combined with our new compact and versatile MK21 first stage for an ideal mid-range system. MK21 First Stage A new compact, balanced piston-controlled first stage with exceptional ScubaPro breathing performance at a mid-range price. The high airflow delivery to the second stage ensures unaffected breathing effort, no matter the tank pressure or depth. Very good resistance to freezing for a compact first stage, due to the external fins which optimize thermal exchange. Compact in size (16 mm smaller than the MK25) but not in features, this modern, striking first stage has a "smart" hose layout for perfect positioning and easy identification.