The Polk Audio Atrium 65SDI All Weather Stereo Speaker is ideal for single speaker stereo performance where a pair of speakers is inconvenient, or as a pair of speakers where high-performance, weather-resistant speakers are needed. The 65SDI has a unique, patent-pending Dual Input/Single Input switch combined with a dual tweeter array that allows this unit to be used either as a single high-performance stereo loudspeaker, or the left-or-right speaker in a high-performance stereo pair. This function is enabled or disengaged via a simple switch located over the binding-post connectors, and sums the complete stereo signal (left and right) or the single left or right signal and mixes the signal to the appropriate tweeter or tweeters for the best performance, smoothest blending and most detailed imaging of any multi-application speaker. The Polk Atrium 65SDI utilizes a 6.5-inch mineral-composite polypropylene cone with butyl-rubber suspension for superior bass and midrange response, as well as dual one-inch metalized dome tweeters with neodymium magnets. Constructed with stainless steel and brass hardware, and an aluminum bracket and grille for rustproof reliability, this unit has special military spec waterproofing features that include a patent-pending waterproof power-port bass vent with a bug-screen for keeping critters out of the cabinet. The Atrium 65SDI features a sculpted front baffle and rounded enclosure that minimize diffraction (caused by sound reflecting off of hard edges) for even more open and lifelike imaging, and two sets of gold-plated five-way binding posts for more secure hook-up options. Built with a sleek black finish and rugged enough for use practically anywhere, the Polk Atrium 65SDI is a great introduction to high-performance sound.