Pressure while keeping water molecules out, resulting in a watertight case that is even easier to openEasier to open it s the classic C clamp design with a secondary movement that works like a pry bar to start the release and offers plenty of leverage to open with a light pullautomatic Pressure Equalization Valve releases built-upStainless steel is made to resist heat, result is less wear and tear on the polyurethane wheelStainless steel reinforced padlock protectors provide added strength and extra security against cutting and theftDouble-throw latches are smartenges and handlesPelican cases are watertight, and the secret is the tongue and groove fit with a polymer o-ring acting as a waterproof sealStainless steel ball bearing wheels last longer and ride somootherThe nylon hub adjacent to the steelAnatomy of a pelican case = Pelican Cases are made with a proprietary combination of homo and co-polmers, using an open cell core and solid wall construction, which is stronger and lighter than a solid core wallAutomatic pressure equalization valve releases built-upO-Ring seal