Amazon.com: H YANKA 10 Inch Subwoofer - 10 Inch Paper Cone Subwoofer Car Audio, Black Steel Basket, Dual Voice Coil 4 Ohm Impedance 10 subwoofer, 1000W MAX Power 10 inch Competition Subwoofer : Electronics
Dayton Audio DCS255-4 10" Classic Subwoofer 4 Ohm
Amazon.com: American Bass HD Series Subwoofer Dual 4 Ohm Voice Coil, 800W AB-HD-8-D4 : Electronics