Alpine R-W12D2 R-Series 12" subwoofer with dual 2-ohm voice coils at Crutchfield
Alpine SWE-1242 Type-E 12" 4-ohm subwoofer at Crutchfield
Alpine Car Audio Systems 800W 12" bandpass subwoofer in custom enclosure 7427282664141 | eBay
Amazon.com: Alpine ALP19-R-W12D4 Car Audio Type R Series Sub Dual 4 Ohm 1500W Peak 12" Subwoofer : Electronics
Alpine Jeep Wrangler Single 12-Inch Alpine Halo R-Series Preloaded Subwoofer Enclosure with ProLink R2-SB12V (Universal; Some Adaptation May Be Required) - Free Shipping
Amazon.com: Alpine SWR-8D4 8" Car Subwoofer : Electronics