Polk Audio's FXi3 (White) High Performance Surround Speakers, Pair (White) One 5.25" Dynamic Balance polymer composite drivers for smooth wide-range response with low distortion. Acoustically inert, asymmetrically braced 3/4" MDF cabinets, finished in white. 1" silk dome Dynamic Balance tweeters on opposing baffles feature neodymium magnets for clear, detailed highs; tweeters are heat-sinked for superior heat dissipation, power handling and reliability. Bi-Pole/Di-Pole Switch conveniently located on front baffle; choose your sound radiation pattern according to your installation requirements, get the best, most realistic diffusion possible for your setup. Butyl rubber surrounds for high performance durability.