The Optimist Buoyancy Bag 48 L is a yellow inflatable bladder with an inflation tube and a lock valve. The bag is made from a heavy-duty polyurethane-coated nylon buoyancy pouch, meaning it is stronger and lighter than traditional buoyancy bags. Using this bag, you can secure it to your Optimist Sailing Dinghy and prevent it from sinking when the boat is capsized.These Optimist Buoyancy Bags are made of polyurethane-coated nylon and are about half the weight and significantly stronger than buoyancy bags made of PVC or PVC-coated nylon. Some bags are available with a twist-lock tube valve. This valve is attached to a piece of tubing. With this valve, the bag can easily and quickly be inflated and deflated. 48 L bags are slightly heavier, but after a capsize, there is a lot less water in the boat.SpecificationsMaterial: Polyurethane-coated nylonColour: YellowSize inflated: 29 cm x 92 cmSize deflated: 44 cm x 98 cmRadius: 5 cmCapacity: 48 LPlease NoteNot to overinflate the Optimist buoyancy bags. When bags are properly filled, they will be soft to the touch. Over-inflated bags may burst when heated up by the sun or rising temperatures. Make sure there are no sharp points in your boat that would snag or puncture the buoyancy bags.