3I Series injection molded waterproof cases are constructed of Ultra high-strength polypropylene copolymer resin and feature a gasketed, waterproof and airtight, submersible design (IP67) that is resistant to corrosion and impact damage. Its Molded-in hinge, patented "trigger release" Latch system, comfortable, snap-down rubber over-molded cushion grip handle, secure stacking, and automatic ambient pressure equalization valve (mil-stud-648c) all contribute to its military grade design.