Alpine Swr-843d 8-Inch 1000 Watt Dual 4 Ohm Type R Subwoofer 8" Subwoofer with Dual 4-Ohm Voice Coils Power Handling: 350W RMS / 900 W RMS Frequency Response: 28-200 Hz Sensitivity: 83.5 dB Top-Mount Depth: 4-1/2"