Fusible Louver, Material Steel, Opening Height 24 In., Opening Width 24 In., Window Height 22 In., Window Width 22 In. The NGP fusible link door louver is fire rated for 1-3/4" thick doors up to 90 minutes. Louver blades close automatically when activated by fire or heat. Features 165 Degrees fusible link. Door louver is made from an 18-ga. cold-rolled steel frame with 18-ga. cold-rolled steel, adjustable "Z" blades, mitered corners secured with reinforcing clips, and a stainless steel spring. Gray primer powder-coat finish.
Very Sturdy and well built. Easy to install, good air flow and is built so as to prevent any see through. Screws for installation were supplied and this is a very good product