SoundQubed HDC418 18 inch Dual 1 ohm Aluminum Competition Subwoofer 2000W RMS 18" Competition Subwoofer, 4 inch Dual 1ohm Aluminum Voice Coil The HDC4 has 9.25 inch diameter multi-layer spider system 8 Gauge Direct Voice Coil Lead Wires 2000 Watt RMS-6000 Watt Peak SPL MONSTER!