Mobile Audio Video Creations : Oxygen Audio Alium 380 15" Subwoofer 4-ohm
SL1779 500W Max / 230W RMS Powered Under-seat Active Slim 7”X9” Subwoofer with Two 4”X6” Passive Radiators, Bass Remote Control and Complete Oxygen Free Copper Wiring Kits - Recoil Audio
O2 OM-8-200 at Onlinecarstereo.com
Amazon.com: Clarion WF2520D 1000 Watts Maximum Power Handling 10" Dual 4Ohm Voice Coil Shallow-Mount Car Audio Subwoofer with (Two) Gravity Magnet Phone Holder Bundle : Electronics