36" x 26" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 10" Round Duct Pipe + Product Details Perfect Fit 190RF 10X20 FBA crafted from heavy gauge Compatible With Duct 7in

+ Product Details Perfect Fit & Easy Sizing - Designed for a 26" x 18" OR 18" x 26" duct opening (measured at the opening)

+ Product Details Perfect Fit & Easy Sizing - Designed for a 12" x 32" or 32" x 12" duct opening (measured at the opening)

actual front end outer dimensions are approximately 18 5/8" width X 10 5/8" height

+ Product Details Perfect Fit & Easy Sizing - Designed for a 14" x 20" OR 20" X 14" duct opening (measured at the opening)

+ Product Details Size - 36"w X 8"h is the size for the duct opening measurement only

36" x 26" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 10" Round Duct Pipe + Product Details Perfect Fit 190RF 10X20 FBA crafted from heavy gauge Compatible With Duct 7in + Product Details Perfect Fit & Easy Sizing Designed for a 26" x 18" OR 18" x 26" duct opening (measured at the opening) + Product Details Perfect Fit & Easy Sizing Designed for a 12" x 32" or 32" x 12" duct opening (measured at the opening)