Boss Audio Systems P126dvc Phantom 12-inch 2300 Watts 4 Ohm Dual Copper Voice Coal Car Audio Stereo Subwoofer Speaker With Poly Injection Cone : Target
Kenwood Road Series 12" Single-Voice-Coil 4-Ohm Subwoofer Black KFC-W120SVC - Best Buy
Amazon.com: H YANKA 12 Inch Subwoofer - 12 Inch Paper Cone Subwoofer Car Audio, Black Steel Basket, Dual Voice Coil 4 Ohm Impedance 12 subwoofer, 1600W MAX Power 12 inch Competition Subwoofer : Electronics
How to Wire a Dual 2 ohm Subwoofer to a 4 ohm Final Impedance | Car Audio 101 - YouTube