Down 4 Sound - Quad 6.5" or 8" Custom Sub Boxes with Kerf
KICKER CompRT Down-Firing 8” Dual-Voice-Coil 2-Ohm Loaded Subwoofer Enclosure Black 48TRTP82 - Best Buy
8" Speaker Box Enclosure Sub Subwoofer Box Car Speaker Box 7.25" Hole – AK Audio
Qpower Qbfordff09208 8 Inch Dual Port Subwoofer Enclosure Box With Underseat Down Fire For Ford F150 Super Crew And Ford F250 And 350 Super Duty : Target
Alpine S-DB8V-TRK Halo Series 8" ported dual subwoofer enclosure with two 8" S-Series subwoofers at Crutchfield