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 but a more steeply-angled baffle design that maximizes critical mid- and high-frequency dispersion over a large area.;Speed-Lock Mounting System for easy, safe one-handed installations even in difficult locations. The greatly simplified mounting procedure means fewer parts to juggle.