Atrium Series Speakers exceed baseline industrial and military specifications for environmental endurance. * (ASTM D5894-UV Salt Fog, Mil Standard 810 Immersion, Mil-Std 883 Method 1009.8 for salt and corrosion.) * Anodized Aluminum Tweeter Domes with Rubber Surrounds are absolutely immune to the elements. * Provide the smooth, broad high-end range you need for larger outdoor spaces * Newly designed tweeter phase cap smoothes the frequency response from 12KHz up to 20kHz, the last audible octave. * Broad Coverage Baffle Design adapted and applied from our current Atrium design. * Speed-Lock Mounting System for easy, safe one-handed installations even in difficult locations. * The greatly simplified mounting procedure means fewer parts to juggle.