Amazon.com: Pioneer TSW312D4 Champion Series 12" 1500 Watt Dual 4 Ohm Voice Coil DVC Car Subwoofer : Electronics
Amazon.com: Car Vehicle Subwoofer Audio Speaker - 12 Inch Competition Grade Pressed Paper Cone, 2 Ohm DVC, Advanced Air Flow, 6000W Power for Stereo Sound System - Gravity Warzone GW12D2 (2 Subwoofers) : Electronics