Kicker 48TRTP82 TRTP 8-inch Thin Down Firing Subwoofer and Passive Radiator Enclosure, 2-Ohm - Used Acceptable - Creative Audio
8 inch Passive Radiator Kit (F8PR) | Midwest Speaker Repair
BOSS Audio Systems CUBE8 8 Inch Car Audio Subwoofer and Amplifier Package – Powered, Built-in Amplifier, Passive Radiator, Remote Subwoofer Control, For Truck, Boxes and Enclosures - Walmart.com
8 inch Passive Radiator Kit (F8PR) | Midwest Speaker Repair