Amazon.com: DR DOUBLE ROCK CB08 Under-Seat Subwoofer Car Audio 600 Watts 8 inch Slim Powered Subwoofer with Built in Amp Active Compact Subwoofer with Amplified+Bass Volume Control Knob : Electronics
Amazon.com: PyleUsa 10-Inch Low-Profile Amplified Subwoofer System - 900 Watt Compact Enclosed Active Underseat Car Audio Subwoofer with Built in Amp, Powered Car Subwoofer w/Low & High Level Inputs - PPLBX10A :