Check the listing for details. SKB 3I-1209-4B - Military Standard Waterproof Case Empty LN. Color: Empty, Condition: Pre-owned. Listed at 95.54 USD. SKB's 3I Series of waterproof cases are the perfect solution for storing and transporting your delicate electronics, A/V equipment, microphones, mixers, cables, computers, percussion, audio equipment, and music accessories. 3I Series injection-molded waterproof cases are constructed of ultra high-strength polypropylene copolymer resin and feature a gasketed, waterproof, airtight, submersible design that is resistant to corrosion and impact damage. Its continuous molded-in hinge; patent pending "trigger release" latch system; comfortable, snap-down rubber over-molded cushion-grip handle; secure stacking; and automatic ambient pressure equalization valve all contribute to this SKB case's military-grade design.