The 48-liter blue Optimist buoyancy bag is constructed from polyurethane-coated nylon, offering a much lighter and stronger alternative to traditional PVC or PVC-coated bags. Featuring a twist-lock tube valve, it enables quick inflation and deflation. While slightly heavier than the 43-liter version, the 48-liter bag ensures less water in the boat after a capsize. Be cautious not to overinflate; the bag should feel soft when properly filled. Overinflation may cause bursting under heat or pressure. Always check for sharp points in the boat that could puncture the bag.