12" X 4" ADJUSTABLE AIR SUPPLY DIFFUSER - HVAC Vent Duct Cover Sidewall or Ceiling 10in diameter + Product Details Perfect Fit Compatible with Duct 4" RG1612AL actual front end outer

+ Product Details Perfect Fit & Easy Sizing - Designed for a 20" x 24" OR 24" x 20" duct opening (measured at the opening)

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

[Outer Dimensions: 10

+ Product Details Size – 10"w X 24"h is the size for the duct opening measurement only

+ Product Details Size - 12"w X 24"h is the size for the duct opening measurement only

12" X 4" ADJUSTABLE AIR SUPPLY DIFFUSER HVAC Vent Duct Cover Sidewall or Ceiling 10in diameter + Product Details Perfect Fit Compatible with Duct 4" RG1612AL actual front end outer + Product Details Perfect Fit & Easy Sizing Designed for a 20" x 24" OR 24" x 20" duct opening (measured at the opening) + Product Details Size – 25"w X 25"h is the size for the duct opening measurement only