Pioneer TS-W307D4 12-Inch 1200-Watt Subwoofer 12";1200W; 400W RMS;SPL: 89 DB;18 HZ - 500 HZ;dual 4 Voice coil; Trickle-down technology from SPL woofers provide maximum performance Dual voice coil design maximizes flexibility; integrated single-sided terminals with 4 bridging adapter