Amazon.com: Alpine R-W12D4 Car Audio Type R Series Sub Dual 4 Ohm 2250W Peak 12" Subwoofer and HA-SWKD Dual Subwoofer Sub Box Install Kit : Electronics
Alpine R2-W12D2 12-inch R-Series Subwoofer with Dual 2-Ohm Voice Coi
Alpine SWR-1242D Type-R 12" subwoofer with dual 4-ohm voice coils at Crutchfield