Atrium Series Speakers exceed baseline industrial and military specifications for environmental endurance;Anodized Aluminum Tweeter Domes with Rubber Surrounds are absolutely immune to the elements, provide the smooth;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;Speed-Lock Mounting System for easy, safe one-handed installations even in difficult locations.