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 Type R 12 Inch 2250 Watt Max 4 Ohm Round Car Audio Subwoofer | R-W12D4 - Walmart.com
Alpine R2-SB12V Single Type R2 12-in Subwoofer in Vented Enclosure - Creative Audio
Alpine R2-W12D4 12” R-Series 750W RMS Subwoofer Dual 4 Ohm Car Audio Sub R2W12D4 | eBay