The Mares Abyss Navy Octopus is an all metal technology second stages that have superior performance over plastic second stages, especially in cold water, due to the high thermal conductivity that limits the freezing effect. Additional benefits are the improved durability, the longer working life and less dry mouth from breathing compressed air. This all metal second stage is made of marine grade brass and then coated with a special fluoropolymer resin finish on the second stage case and all key components to prevent ice crystals from forming in extreme cold conditions. The patented mesh design of the second stage cover reduces the pressure of water flowing onto the regulators diaphragm and minimizes free-flow. Even in a strong current it eliminates the need for a knob to de-tune your air delivery system, advance technology through basic physics. All Mares second stages are a reliable downstream demand valve design and offer the unique patented Vortex Assisted Design (VAD) system. The air bypass tube conveys air to the mouthpiece creating a swirling vortex with a low-pressure area in the center that keeps the diaphragm down during inhalation, for very sensitive and easy breathing at all depths. Mares Abyss Navy Octopus weighs 15 oz. (427 g) with the hose, has a 39.4" (100cm) long 3/8" threaded hose. Regulator is Nitrox ready up to 40% oxygen out-of-the-box.