Single alpine type r 12" ripping car apart - YouTube
Alpine SWS-1243D Type-S 12" subwoofer with dual 4-ohm voice coils at Crutchfield
Amazon.com: Universal Car Stereo Vented Port Single 12" Alpine S-W12D4 Type S Car Audio Subwoofer Custom Sub Box Enclosure Package New Without Amp : Electronics
Alpine S-Series 12" Dual-Voice-Coil 4-ohm Subwoofer Black S-W12D4 - Best Buy
Best Buy: Alpine X-Series 12" Dual-Voice-Coil 4-Ohm Subwoofer Black X-W12D4