Amazon.com: Earthquake Sound SLAPS-M12 12-inch Passive Radiator for Home and Mobile Audio Subwoofer Enclosures : Everything Else
JBL ASB6112 4000W 12-inch Passive Subwoofer - Black | Sweetwater
Klipsch THX-1200-SW 12" Passive Subwoofer
Vibe Black Air 12" Passive Radiator Subwoofer Enclosure BLACKAIRC12-V6 - 12v Electronics
Wet Sounds Revo 12 PSE (Black w/black grille) Revo Series sealed marine subwoofer enclosure with 12" 4-ohm subwoofer and 12" passive speaker at Crutchfield
Electro Voice ELX200-12S 12" Passive Subwoofer - Single - Vintage King