Polk DSWPRO 660wi 12-inch Wireless-ready Powered Subwoofer Feed forward distortion suppression technology limits the risk of excessive distortion or damage. Four preset Room Optimizer options and Polks exclusive PRO technology program in the optimal bass and blending setting for your room. Our state-of-the-art Klippel distortion analyzer optimizes the woofers motor structure, voice coil alignment and suspension to ensure the best, most efficient performance even at extreme listening levels. LFE, line level inputs and outputs and 5-way binding posts for speaker level inputs allows easy connection to any system. The Night Mode setting temporarily lowers the subs intensity with a quick and easy toggle from the remote control.