Return Air Grille Overall Depth 1/4 in Overall Height 3 3/8 in Overall Width 13 1/8 in Maximum Opening Height 2 in Maximum Opening Width 12 in Filter Depth Not Applicable Filter Height Not Applicable Filter Width Not Applicable Grille Color White Grille Material Steel Material Steel Damper Material Steel Bar Spacing 1/2 in Face Design Louvered Airflow Directions One-Way Adjustable Blades No Mounting Location Ceiling or Wall Mounting Style Surface Mount Blade Angle 45 Degrees