Alpine 12" Single-Voice-Coil 4-Ohm Loaded Subwoofer Enclosure Black SWT-12S4 - Best Buy
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Amazon.com: Alpine ALP19-R-W12D4 Car Audio Type R Series Sub Dual 4 Ohm 1500W Peak 12" Subwoofer : Electronics
Alpine Type-S SWS-12D4 12" 1500 Watt Dual 4-Ohm Car Audio Subwoofer Sub SWS12D4 | Audio Savings