18"W X 18"H [Duct Opening] Steel Air Vent Return Grille - HVAC VENT DUCT COVER DIFFUSER - [Outer Dimensions: 19.75"W X 19.75"H] Compatible With Duct 10in + Product Details Size – 4 X 12 Is CRFG2028 Width_14in

+ Product Details Size – 8"w X 16"h is the size for the duct opening measurement only

+ Product Details Size - 18"w X 28"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 16" x 30" OR 30" X 16" duct opening (measured at the opening)

actual front end outer dimensions are approximately 22 5/8" width X 42 5/8" height -

875" width X 20" height

18"W X 18"H [Duct Opening] Steel Air Vent Return Grille HVAC VENT DUCT COVER DIFFUSER [Outer Dimensions: 19.75"W X 19.75"H] Compatible With Duct 10in + Product Details Size – 4 X 12 Is CRFG2028 Width_14in + Product Details Size – 8"w X 16"h is the size for the duct opening measurement only + Product Details Size 18"w X 28"h is the size for the duct opening measurement only