Fits 18x12 Duct Opening Stamped Steel Return Air Grille Vent Cover Grille for Sidewall and Ceiling in White Surface Dimensions: 19.75"W X 13.75"H (18" W x 12" H Duct Opening) actual outsize overall dimensions is

actual outsize overall dimensions is 14'' X 14''

Easy adjust air flow control with central lever

If your duct opening size is 12” x 8”

15" long heavy duty steel construction with white powder coating finish

If you measure outside or surface size

Fits 18x12 Duct Opening Stamped Steel Return Air Grille Vent Cover Grille for Sidewall and Ceiling in White Surface Dimensions: 19.75"W X 13.75"H (18" W x 12" H Duct Opening) actual outsize overall dimensions isThe Listed size 18"x12" is for inside duct opening measurement, actual outside dimension is 19. 75"x13. 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