Alpine R2-W12D2 R Series 12" subwoofer with dual 2-ohm voice coils at Crutchfield
Universal Fit Alpine S-W12D2 Type S Triple 12" Subwoofer Loaded Sub Box New 793276242150 | eBay
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