Amazon.com: Alphasonik AS12DF 12" 1500 Watts 4-Ohm Down Fire Shallow Mount Flat Enclosed Sub woofer for Tight Spaces in Cars and Trucks, Slim Thin Loaded Subwoofer Air Tight Sealed Bass Enclosure :
Amazon.com: Atrend Bbox 12AME 12-Inch Single Sealed Shallow Mount Downfire Enclosure, black (12AME*) : Electronics
Amazon.com: KICKER TRTP 12-inch (30cm) Thin Down Firing Subwoofer and Passive Radiator Enclosure, 2-Ohm, RoHS Compliant : Electronics