1.50 ft³ @ 34Hz Ported 3/4" MDF SQ/SPL Enclosure Box for Dual 8" Car Subwoofers | eBay
BT Series 8” Passive Bass Tubes – Bazooka
Amazon.com: IMC Audio PPA8SS 8 Inch Car Speaker Box Enclosures - 8 Subwoofer Box for Great Sound Quality Home & Vehicle Car Speakers 8 Inch Speaker Terminal One 8" Sub Box - Charcoal : Electronics