Build a better sound system with this Klipsch Reference bookshelf speaker. The 1-inch aluminum tweeter and square Tractrix horn provide clear, natural high tones, while the 4-inch spun-copper woofer produces deep, distortion-free bass. This Klipsch Reference bookshelf speaker lets you crank up the volume for parties with a sensitivity of 90 dB. | Klipsch | | Reference 4" Bookshelf Speakers (Pair | Black | Best Buy