iSeries 3613-12 Watertight Utility Case empty w/Wheels and Tow Handle SKB iSeries Injection Molded Mil-Standard Waterproof Cases are molded of ultra high-strength polypropylene copolymer resin, and feature a gasket sealed, water and dust tight, submersible design (MIL-C-4150J) that is resistant to corrosion and impact damage. Standard features also include a molded-in hinge, patented trigger release latch system, comfortable, snap-down rubber over-molded cushion grip handles, automatic ambient pressure equalization valve (MIL-STD-648C), and resistance to UV, solvents, and fungus (MIL-STD-810F).