Fits 20x8 Duct Opening Stamped Steel Return Air Grille Vent Cover Grille for Sidewall and Ceiling in White Surface Dimensions: 21.75"W X 9.75"H (20" W x 8" H Duct Opening) The Listed size 24"x20" is

The Listed size 24"x20" is for inside duct opening measurement

Actual outside measurement is 16" x 10"

Effortless Airflow Control: Our functional floor register is equipped with an easy-to-use airflow control switch

actual outsize overall dimensions is 13

1/2" ID for high water flow

Fits 20x8 Duct Opening Stamped Steel Return Air Grille Vent Cover Grille for Sidewall and Ceiling in White Surface Dimensions: 21.75"W X 9.75"H (20" W x 8" H Duct Opening) The Listed size 24"x20" isThe Listed size 20"x8" is for inside duct opening measurement, actual outside dimension is 21. 75"x9. 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