This is the Scubapro S270 Balanced Scuba Diving Octopus Features: Air-balanced valve smoothes out the inhalation effort when diving at varying depths and supply pressures Lightweight casing, made of a fiberglass-reinforced nylon core and a special PU outer layer, is extremely durable plus helps reduce jaw fatigue and improve diving comfort Technopolymer plastic barrel with a metal thread and a balanced valve helps save weight and provides a surface that ice crystals can&';t grab onto when diving in extreme cold water Dive/predive switch prevents freeflows when not being used Compact and efficient exhaust tee minimizes exhalation effort Compact Hi-Flow mouthpiece is comfortable, made with FDA-approved silicone and features a large cross-section to maximize airflow High-viz yellow front cover stands out, making it easy to spot when needed High-viz yellow super-flow hose is 39in/1m long with an oversized bore that allows more air to flow on each inhalation The ideal backup breather for your dive system, the S270 Octopus is tough, reliable, and easy to use. Its air-balanced design can be counted on to deliver top-notch breathing performance when you need it most.