Amazon.com: Seismic Audio - SA-BPT08-A - Active 8 Inch Car Audio Subwoofer Tube Speaker - 400 Watt Sub Speaker Enclosure 4 Ohm with Rear Vent : Electronics
Amazon.com: Pyle 8-Inch Low-Profile Amplified Subwoofer System - 600 Watt Compact Enclosed Active Marine Underseat Car Subwoofer with Built in Amp, Powered Car Subwoofer w/Low & High Level Inputs PLMRSBA8 : Electronics