Dayton Audio PSS545HE-4 Vortex 21" Professional Subwoofer with 5" Voice Coil 4 Ohm
Boss Audio 8-Inch Dual Voice Coil 4-Ohm 1000-Watt Car Subwoofer (2 Pack) P80DVC - Walmart.com
Kole Audio 12 Inch Single Magnet Double Voice Coil Subwoofer - KA-12D4 Selangor, Malaysia, Kuala Lumpur (KL), Seri Kembangan Supplier, Suppliers, Supply, Supplies | One Biz Online Sdn Bhd
Sundown Audio SA Series Dual 4 Ohm Voice Coil | The Lord of Bass