Amazon.com: Pioneer TS-A301S4 Champion Series 12" 1600 W Max Power, Single 4 Ohm Voice Coil - Component Subwoofer : Electronics
Pioneer Champion Series 12" Dual-Voice-Coil 4-Ohm Subwoofer Black TSW311D4 - Best Buy
Pioneer Electronics on Twitter: "The Champion Series Subwoofers feature an enclosed basket structure that is designed to support the steel basket by reducing the spread of vibration that causes bass loss frequency. #
Pioneer TS-300S4 12" 30cm Champion Series Single Voice Coil Car Subwoofer 1400W 3783707927999 | eBay