HOLLIS BACK MOUNTED COUNTERLUNGS Backmounted Counterlung positions lungs behind the diver leaving the chest free for attachment of additional tanks and accessories. This also allows improved streamlining with less drag and better horizontal trim. Features a 2 piece bag design for improved WOB performance and easy removal of the internal lung for cleaning or replacement. ADV Upstream Valve design is reliable and resistant to free flow which is a benefit for the addition of valuable diluent gas. All gas delivery systems on the Prism 2 have both automatic and manual function. Water Trapping T-pieces keep excess water from the breathing loop inside the counterlung for easy draining. Streamlined Hose Fittings keep LP hoses routed inside closest to the diver which avoids overhead interference. Machined DIL and O2 MAV controls ensure a rugged and reliable design, also allowing offboard gas plugin on both sides. Hollis Prism 2 Back Mount Counterlung Kit 240.6606