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 r12 1st Gen Subwoofers d4 | AVS Forum
Amazon.com: Alpine ALP19-R-W12D4 Car Audio Type R Series Sub Dual 4 Ohm 1500W Peak 12" Subwoofer : Electronics
2) Alpine Type R 12 Inch 2250 Watt Max 4 Ohm Round Car Audio Subwoofer - Walmart.com