Blade Material: White Painted Aluminum , Blade Material Thickness: 26 ga. , Blade Orientation: Parallel Blades , Blade Seal Material: Felt , Blade Type: Flat Blade , Fits Fan Diameter: 36" , Frame Finish: Galvanized , Frame Opening Height: 36" , Frame Opening Width: 36" , Max. Air Velocity: 2500 fpm , Max. Ambient Temp.: 180 Deg. F , Max. Pressure: 1" wc , Max. Velocity: 2500 fpm , Mounting Hole Dia.: 1/4" , Mounting Hole Size: 9/32 x 1/2" , Mounting Location: Wall , Mounting Position: Vertical , Open Depth: 6 1/4" , Overall Dia.: 39" , Overall Height: 39" , Overall Length: 5 3/4" , Overall Width: 39" , Rough Opening Diameter: 36.5" , Rough Opening Length: 36 1/2" , Rough Opening Shape: Square , Switch Action: Normally Closed , Tie-Rod Finish: Galvanized , Tie-Rod Material: Steel