Amazon.com: Visaton R10S 4" Full Range Speaker 8 Ohm : Electronics
Amazon.com: Pyle 6.5 Inch Mid Bass Woofer Sound Speaker System - Pro Loud Range Audio 300 Watt Peak Power w/ 4 Ohm Impedance and 60-20KHz Frequency Response for Car Component Stereo PLG64,Yellow : Electronics
Amazon.com: KICKER 45KMF104 10" Weather-Proof Subwoofer for Freeair Applications 4 Ohm 45KMG10W 10" LED Grille (White) : Electronics
Amazon.com: KICKER Comp 10" (25cm) Subwoofer in Down Firing Encl, 4-Ohm, RoHS Compliant : Electronics
Amazon.com: 5 CORE 15 inch Subwoofer Replacement PRO DJ Speaker Sub Woofer Loudspeaker Wide Full Range Loud Aluminum Frame 2200W PMPO, 90oz 185mm Magnet, y-30 Grade Powerful Magnet : Electronics
Amazon.com: Pyle 8 Inch Car PA Woofer - 500 Watt High Powered Car Audio Sound Component Speaker System w/ 1.5" Kapton Voice Coil, 55-6 kHz Frequency, 89.2 dB, 8 Ohm, 40 oz Magnet - PylePro PPA8 , Black : Electronics