Best Buy: Alpine S-Series 12" Dual-Voice-Coil 4-ohm Subwoofer Black S-W12D4
Car subwoofer 12 "30 cm ALPINE X-W12D4 sound electronics columns 84.3dB subwoofers for cars acoustics auto audio parts components speaker - AliExpress
Car Subwoofer 12 "30 Cm Alpine Swe-1244e Sound Electronics Columns 88.7db Subwoofers For Cars Acoustics Auto Audio Parts Components Speaker - Subwoofers - AliExpress
Alpine 12 Inch Bass Line Subwoofer (W12S4) | SK Customs Car Audio & Home Theater | Atlanta | Norcross | Duluth | John's Creek
Amazon.com: Alpine W12S4 12-inch Single 4 Ohm Subwoofer : Electronics
Alpine SWE-1242 Type-E 12" 4-ohm subwoofer at Crutchfield
Best Buy: Alpine S-Series 12" Dual-Voice-Coil 4-ohm Subwoofer Black S-W12D4
ALPINE SWS-1242D 12" Dual 4 ohm Type-S Series Car Subwoofer. Tested works. Used | eBay
Alpine S2-W12D4 at Onlinecarstereo.com
Alpine S-W12D2 S-Series 12" subwoofer with dual 2-ohm voice coils - Breakers Stereo and Performance