Door Louver Material Aluminum Finish Clear Anodized Louver Opening Height 12 1/2 in Louver Opening Width 20 1/2 in Rough Opening Height 12 1/2 in Outside Height 14 1/8 in Outside Width 22 1/4 in Free Area 0.9 sq ft Flange Width 1 1/4 in Maximum Door Thickness 2 1/4 in Minimum Door Thickness 1 3/8 in Rough Opening Width 20 1/2 in Blade Angle 45 Degrees Adjustable Blades No Intake or Exhaust Application Exhaust Intake Includes Fasteners Number of Blades 17