12"W X 4"H [Duct Opening] Steel Air Vent Return Grille - HVAC VENT DUCT COVER DIFFUSER - [Outer Dimensions: 13.75"W X 5.75"H] w16h16 25" X 20"opening dimension (vent

25" X 20"opening dimension (vent opening) - actual total grille size is approx

+ Product Details Size – 36"w X 30"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 36" x 18" OR 18" x 36" duct opening (measured at the opening)

actual front end outer dimensions are approximately 26 5/8" width X 24 5/8" height

12"W X 4"H [Duct Opening] Steel Air Vent Return Grille - HVAC VENT DUCT COVER DIFFUSER - [Outer Dimensions: 13.75"W X 5.75"H] w16h16 25" X 20"opening dimension (vent+ Product Details Size 12"w X 4"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 13. 75" width X 5. 75" height. Design Easy unrestricted airflow for your HVAC system 50 angled to provide maximum airflow. High Quality Solid stamped steel with counter sunk screw holes (screws included) and no sharp edges. Powder Coat Finish Smooth, shiny, scratch resistant, beautiful. Looks like it was just waxed.