This Premium Line Of Attractive Architectural Louvered Grilles Will Enhance The Appearance Of Any Building. Each Louvered Grille Is Made Of , Durable, Extruded Aluminum with A Baked Enamel Finish Containing 50% Kynar Resin To Resist Rust and Corrosion. These Louvered Grilles Are Designed To Be Installed Easily From Inside The Room To Avoid Long Ladders or Expensive Aerial Lifts. Louvered Grille Mounts Securely To The Rear Of The Wall Sleeve and Exceeds Free Area The 65 % Minimum Requirement Specified By Most Ptac Manufacturers. Free Area Is The Minimum Area Of The Opening In An Air Inlet or Outlet In Which Air Can Pass Freely.