Fits 20x20 Duct Opening Stamped Steel Return Air Grille Vent Cover Grille for Sidewall and Ceiling in White Surface Dimensions: 21.75"W X 21.75"H (20" W x 20" H Duct Opening) It deflects the air alongside

It deflects the air alongside the wall to soften the air flow hence creating desired comfort level in your room

3) select the listed size that match the duct opening size

Stamped Face Steel Construction with 1/2" fin spacing for high air flow

The Listed size 24"x14" is for inside duct opening measurement

Fits 20x20 Duct Opening Stamped Steel Return Air Grille Vent Cover Grille for Sidewall and Ceiling in White Surface Dimensions: 21.75"W X 21.75"H (20" W x 20" H Duct Opening) It deflects the air alongsideThe Listed size 20"x20" is for inside duct opening measurement, actual outside dimension is 21. 75"x21. 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