Kicker 49PTRTP10 Compact down-firing 400-watt powered enclosure with CompRT® 10" shallow-mount subwoofer and passive radiator at Crutchfield
Amazon.com: Pyle 8-Inch Low-Profile Amplified Subwoofer System - 600 Watt Compact Enclosed Active Underseat Car Audio Subwoofer with Built in Amp, Powered Car Subwoofer w/Low & High Level Inputs PLBX8A : Electronics