18TBX100 - 2000W Woofer Speaker =================================== Nominal Diameter - 18 inchs Max Output Power - 2000 Watts R.M.S. Voice coil size - 4.5 inches Impedance - 8 Ohms Magnet - Ferrite Sensitivity - 105dB Woofer Speaker with 4.5inch Voice Coil Suitable for High Power Base-Bin / Sub-Woofer Speakers