This is the XS Scuba Companion Travel BC Air Cell Features: Back Inflation Style Air Cell Converts Pony Pac Harness to Travel BCD System Lift: 30 lbs. (13.61 kg) Weight (with Pony Pac Harness): 5 lbs. (2.27 kg) 40% Lighter than Traditional BCD&';s Easy to Install, Back Inflator Design Rear Pull Dump/Over Pressure Relief Valve Time Proven and Reliable Alliance Inflator Mechanism Alliance Inflator: Cable Activated Pull Dump Valve Assembly Includes: Low Pressure QD Hose Durable Nylon Outer Bag Strong and Reliable Urethane Inner Air Cell Easy to install, back inflator design with rear pull dump/over pressure relief valve on right side. The Companion Bladder also has the time proven and reliable Alliance Inflator Mechanism with a BCD low-pressure QD hose for attachment to your regulator first stage. The Alliance Inflator has a cable activated pull dump valve assembly at the top of the inflator mechanism for easy buoyancy control. The Companion Bladder has a durable nylon outer bag with a strong and reliable urethane inner air cell. "