SKB iSeries 3021-18BS Waterproof Case for Bose F1 Subwoofer High quality dense PE Foam for protection Oversized heavy-duty handles and wide-set double wheels Ultra high-strength polypropylene copolymer resin UV, solvent, corrosion and fungus resistant (MIL-STD-810F) Complete gasket seal makes these cases absolutely watertight (MIL-STD-C-4150J)