18" ferrite woofer provides 1000Wrms power handling (AES Standard) and 97dB sensitivity4" high temperature Inside/Outside voice coil efficiently dissipates heat, preventing sensitivity loss through thermal compression Flexural TM surround for greater excursion control Double suspension for exceptional linearity at the highest excursions Low frequency response, down to 30HzSmart chassis design minimizes acoustic distortion Specially treated, weather-resistant cone