JBL Grand Touring Series GTO1204D 12" subwoofer with dual 4-ohm voice coils at Crutchfield
Amazon.com: JBL GT-BassPro12 12-Inch (300mm) Car Audio Powered Subwoofer System, black : Electronics
JBL Stadium 1224 Stadium Series 12" subwoofer with switchable 2- or 4-ohm impedance - Breakers Stereo and Performance
JBL Club WS1200 | 12" Club Series Shallow-mount Subwoofer
JBL EON712 1300W 12-inch Powered PA Speaker | Sweetwater
SSW-2 | Dual 12” (300mm) Passive Subwoofer
Amazon.com: JBL Club WS1200 12" Shallow Mount subwoofer w/SSI (Selectable Smart Impedance) Switch from 2 to 4 ohm Bundled with Alphasonik Earbuds : Electronics