RCF LF18X451 18-Inch Woofer 4,5 - inch fiberglass Inside/Outside copper voice coil 3600 Watt continuous program power handling 97 dB Sensitivity 30 Hz - 1 kHz Frequency range Dual Forced Hyper venting System Dual spider designed with silicon based damping control BL of 30.5 Txm to provide a faster and accurate low frequency