Custom Ported Subwoofer Box Sub Enclosure for 1 12" JBL W12GTi MkII Sub ~ 32Hz | eBay
Amazon.com : JBL Stage1220B Stage Series Dual 12 Inch Ported Loaded Enclosure - 500 Watt, 2-Ohm : Electronics
JBL BassPro 12 | 12" (300mm) Car Audio Powered Subwoofer System with Slipstream Port Technology
Amazon.com: JBL SUBBP12AM - 450 Watts (150W RMS) 12” Amplified 12 in. Ported Subwoofer with Sub Level Control and Distortion Free Bass with Gravity Magnet Phone Holder Bundle : Electronics