Pioneer TS-A120D4 A-Series 12" subwoofer with dual 4-ohm voice coils at Crutchfield
Amazon.com: Pioneer TSW312D4 Champion Series 12" 1500 Watt Dual 4 Ohm Voice Coil DVC Car Subwoofer : Electronics
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
Hertz Mille Pro Shallow MPS 250 S2 Shallow 10 in. (250mm) 2Ω SVC Subwoofer incl. grille - Creative Audio
Pioneer TS-3003D4 Subwoofer 2000 watt 12” | eBay
Pioneer Sealed 12 in. 1300-Watt Active Subwoofer with Built-in Amp TS-WX1210A - The Home Depot
PIONEER TS-D12D2 12" DUAL 2-OHM VOICE COIL COMPONENT SUBWOOFER 2000W MAX POWER | 702MOTORINGLASVEGAS