Best Buy: Pioneer Champion Series PRO 12" 4-Ohm Subwoofer Black TSW3003D4
Amazon.com: Alphasonik NSW412 Neuron 400 Series 12” 1500 Watts Max / 500 Watts RMS Dual 4 Ohm Car Subwoofer w/ High Grade Magnet Non Pressed Paper Carbon Stitched Cone Cooling Rings System
Pioneer Champion Series TS-A301S4 1600 Watts 12" Single 4 Ohm Car Subwoofer Sub 884938496056 | eBay