Mini Audio Full Range Speaker Stereo Woofer Loudspeakers Box Diy 2 Inch 4 Ohm 3W | eBay
Bluave M10s42 10" Series High Power 600w Marine Subwoofer 4-ohm With 10" Universal Marine Sub Box Enclosure For Cars, Trucks, Powersports, Utvs, Go... : Target
Kicker 12" 4 Ohm Ported Subwoofer Box | P.C. Richard & Son