Amazon.com: DS18 SLC12S Car Subwoofer Audio Speaker - 12" in. Paper Glass Fiber Cone, Black Steel Basket, Single Voice Coil 4 Ohm Impedance, 500W MAX Power and Foam Surround for Vehicle Stereo
Scan-Speak Discovery 30W 12" Subwoofer Kit
Kenwood Excelon P-XW1221D Ported 2-ohm enclosure with two 12" subwoofers at Crutchfield
JBL BassPro 12 Ported powered subwoofer with 12" sub and 150-watt amp at Crutchfield
Insignia 12 inch Speaker / Subwoofer Car Sound System | eBay
Amazon.com: Pyle 12' Car Audio Speaker Subwoofer - 1600 Watt High Power Bass Surround Sound Stereo Subwoofer Speaker System - Non Press Paper Cone, 90 dB, 40 Ohm, 60 oz Magnet, 2