BassPro SL | Powered, 8" (200mm) car audio under seat woofer system
Focal ISUB Twin Sub Powerful Compact Passive Underseat Car Subwoofer 2x100w RMS | eBay
STA-10 10" Amplified Bass Enclosure
Amazon.com: DS18 SQBASSx2 7x9 UnderSeat Slim Amplified Car/Truck Subwoofer with a 4x6 Passive Radiator 1200W Peak Power / 230W RMS - Remote BASS Knob Included - Powered Sub in Ported Enclosure for