With SSI technology for optimum impedance, the JBL Series III Subwoofer lets you never have to compromise audio quality and flexibility again. Being the third series of its kind, these high performance speakers give sound you can rely on, featuring special aero-cooled voice coils to boost power handling for an extensive lifetime of continuously smooth, hiccup-free sound. The JBL Series III subwoofer comes at an impressive 91dB, reinforcing its crisp and clear audio quality. Step up to the Series III for your best subwoofer yet! Subwoofer Features Type: Single Amplifier Power (Peak): 1500W Amplifier Power (RMS): 500W Frequency Response: 25Hz - 175Hz Dimensions (H x W x D): 18mm x 282mm (cut-out); 324mm (outer) x 177mm