16" X 16" [Duct Opening] 3-Way Fixed Curved Blade Air Supply Diffuser Register Vent Cover Grille [Outer Dimensions: 17.75"W X 17.75"H] Width_20in + Product Details Size - SV2414 HP Product Details Perfect Fit 12" Round Duct Pipe

+ Product Details Size - 36"w X 20"h is the size for the duct opening measurement only

Actual Filter Size – 7 3/4"w x 25 3/4" x 1"

+ Product Details Size - 25"w X 32"h is the size for the duct opening measurement only

Design – These Supply Diffusers with integral round necks are recommended for heating

+ Product Details Size – 8"w X 34"h is the size for the duct opening measurement only

16" X 16" [Duct Opening] 3 Way Fixed Curved Blade Air Supply Diffuser Register Vent Cover Grille [Outer Dimensions: 17.75"W X 17.75"H] Width_20in + Product Details Size SV2414 HP Product Details Perfect Fit 12" Round Duct Pipe + Product Details Size 36"w X 20"h is the size for the duct opening measurement only Actual Filter Size – 7 3 4"w x 25 3 4" x 1"