Pioneer TSWH500A TS-WH500A 8 1/4" Sealed Active Subwoofer 150 watts Max power (50 watts nominal) Hvt stands for horizontal vertical transforming technology which transforms horizontal movement into vertical movement of a woofer diaphragm to produce true, powerful and wide-range bass. Significantly reduced physical depth, while maintaining greater excursion and linearity for superior bass reproduction, natural sound quality and higher output. Subwoofer will fit easily in a wide range of vehicle applications (Compact and subcompact vehicles, hybrid vehicles, trucks and SUVs, etc.) Impedance 4 ohms/ frequency response 20 Hz to 200 Hz