Amazon.com: Harmony Audio HA-C124 Car Stereo Competition Carbon 12" Sub 2200W Dual 4 Ohm Subwoofer : Electronics
Amazon.com: Q Acoustics Q B12 Subwoofer Carbon Black - Featuring Infinite Baffle Enclosure, 12" Driver, 220 Watt Class D Amplifier, 1.97" Voice Coil - Active Subwoofer for Home Theater Sound System : Electronics