This is the Aqua Helix Pro Scuba Diving Octopus Features: Type of second stage Pneumatically balanced Controls Venturi switch Breathing resistance Preset Mouthpieces 2ea. - A Comfo-Bite, installed, and a standard with bite wings in the box Lip shield Yes Heat Exchanger for freezing resistance Standard on all models 2nd Stage Weight 175 g 2nd Stage Weight Supreme model178 g Hose length 730 mm Overall work of breathing (WOB) scores Avg. 0.80 joules/liter Nitrox compatible Yes, to 40% O2 when new, out of the box Second Stage Pneumatically-balanced resulting in smooth and easy breathing Heat exchanger (patented) which surrounds the valve mechanism, dissipates the cold caused by gas expansion while drawing in the warmth of the ambient water Easy-to-grip venturi lever prevents unwanted freeflow at the surface while giving a performance boost at depth Includes 1m yellow hose and yellow front cover making it easy to locate in an emergency The Helix Pro octopus provides the same great performance as the Helix Pro primary second stage.