Amazon.com: Gravity 2X 6.5 Inch 600 Watt Car Audio Subwoofer w/ 4 Ohm DVC 6.5" Sub Pair - Feature Dual Voice Coil, Thick Magnet, Design for Car, ATV, Van, High Performance Car Show : Electronics
6.5 Inch 50W at 4 Ohm High Performance 2 Way Speaker with Crossover Dual Voice Coil and Dual Tweeter - China Dual Voice Coil and Dual Tweeter and Smart Home Ceiling Speaker
Sundown Audio U Series V.2 6.5" Subwoofer Dual Voice Coil 2/4 Ohm 800W Peak | eBay
Amazon.com: Pyle Car Vehicle Subwoofer Audio Speaker - 6.5 Non-Pressed Paper Cone, Black Plastic Basket, Dual Voice Coil 4 Ohm Impedance, 600 Watt Power, Foam Surround for Vehicle Stereo Sound System -PLPW6D : Electronics
Goldwood Shielded Dual Voice Coil 6.5 in. Woofer 90-Watt 8 ohm Sub Speaker GW-406D - The Home Depot