Alpine SWR-1242D Type-R 12" subwoofer with dual 4-ohm voice coils at Crutchfield
Alpine Type R 12" SWR-1242D Subwoofer | eBay
Alpine SBR-S12D4 Type-R 12" Subwoofer Enclosure - Signature Car Sound
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 Type R 12 Sub Woofer w/Box - general for sale - by owner - craigslist
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