Fits 24x14 Duct Opening Stamped Steel Return Air Grille Vent Cover Grille for Sidewall and Ceiling in White Surface Dimensions: 25.75"W X 15.75"H (24" W x 14" H Duct Opening) Measure the size of the

Measure the size of the air duct opening(the size of the “hole” )

If the hole is 25" wide by 16" tall

For example: If the hole on the wall is 16" wide by 25" tall

The Listed size 12"x8" is for inside duct opening measurement

Width vs Height The first measurement in a return grille size is the width(horizontal measurement)

Fits 24x14 Duct Opening Stamped Steel Return Air Grille Vent Cover Grille for Sidewall and Ceiling in White Surface Dimensions: 25.75"W X 15.75"H (24" W x 14" H Duct Opening) Measure the size of theThe Listed size 24"x14" is for inside duct opening measurement, actual outside dimension is 25. 75"x15. 75" Stamped Face Steel Construction with 1 2" fin spacing for high air flow applications. Screws are included for easy installation White Powder coating with matte finish Individually packed with cardboard box for ultra protection