26" x 24" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 14" Round Duct Pipe Example: If your hole is 4 X 12 Is CRFG2028 Width_14in

Example: If your hole is 20" wide by 14" tall

+ Product Details Perfect Fit & Easy Sizing - Designed for a 36" x 32" OR 32" x 36" duct opening (measured at the opening)

actual front end outer dimensions are approximately 24 5/8" width X 16 5/8" height

with an additional 1 7/8" width and 2" height

+ Product Details Size - 12"w X 12"h X 2"d (for duct opening measurement only)

26" x 24" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 14" Round Duct Pipe Example: If your hole is 4 X 12 Is CRFG2028 Width_14in Example: If your hole is 20" wide by 14" tall + Product Details Perfect Fit & Easy Sizing Designed for a 36" x 32" OR 32" x 36" duct opening (measured at the opening)