Best Buy: Pioneer Champion Series 12" Single-Voice-Coil 4-Ohm Subwoofer Black TSW310S4
Pioneer TS-W310D4 Champion Series 12" subwoofer with dual 4-ohm voice coils at Crutchfield
PIONEER TS-W311S4 CHAMPION SERIES 12" 4-OHM SUBWOOFER 1,400 WATT (400 W RMS) NEW | eBay
TS-W308D4 - 12" Champion Series Subwoofers with 1400 Watts Max. Power | Pioneer Electronics USA
Amazon.com: Pioneer TS-A300D4 12 Inch 1500 Watts Max Power Dual 4-Ohm Voice Coil A Series Car Audio Stereo Subwoofer Loudspeakers / Free Alphasonik Earbuds : Electronics
Amazon.com: Pioneer TS-A301D4 Champion Series 12" 1600 W Max Power, Dual 4 Ohm Voice Coil - Component Subwoofer : Electronics
2014 Pioneer Champion Series PRO Subwoofer - YouTube
TS-A301D4 - 12" - 1600 W Max Power, Dual 4 Ohm Voice Coil, Champion Series- Component Subwoofer | Pioneer Electronics USA