Cadence Acoustics S1W8-D4 500 Watt Peak 8-Inch Dual Voice Coil 4 Ohm Subwoofer RMS Power: 250 Watts/PEAK Power: 500 Watts Frequency Response: 28Hz - 750Hz Sensitivity: 90dB System Impedance: DVC 4 Ohms Mounting Depth: 3.7 inches