4" X 8" Or 8" X 4" Heavy Duty Floor Grille - Fixed Blades Air Grille - Brown [Outer Dimensions: 5.75 X 9.75] Height_12in Actual Filter Size – 21

Actual Filter Size – 21 3/4"w x 25 3/4" x 1"

+ Product Details Size – 36"w X 12"h is the size for the duct opening measurement only

Actual Filter Size – 11 3/4"w x 13 3/4" x 1"

+ Product Details Size - 14"w X 10"h is the size for the duct opening measurement only

Electrical Connections: Turn off the main power supply before making any electrical connections

4" X 8" Or 8" X 4" Heavy Duty Floor Grille - Fixed Blades Air Grille - Brown [Outer Dimensions: 5.75 X 9.75] Height_12in Actual Filter Size – 21+ Product Details Size 4"w X 8"h or 8" x 4" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 5. 75" width X 9. 75" height. High Quality High grade steel construction meant for high foot traffic areas. Installation Location Floor. Design Easy drop in installation. Powder Coat Finish Smooth, shiny, scratch resistant, with no sharp edges. Looks like it was just waxed. Quality Packaging Carefully