16" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Grille + Product Details Size – 14" Round Duct Pipe For 10 duct opening FR M 414 White

+ Product Details Size – 6" x 8" or 8" x 6" is the size for the duct opening measurement only

+ Product Details Size - 34"w X 6"h is the size for the duct opening measurement only

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

+ Product Details Size - 16"w X 18"h is the size for the duct opening measurement only

16" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Grille + Product Details Size – 14" Round Duct Pipe For 10 duct opening FR M 414 White + Product Details Size – 6" x 8" or 8" x 6" is the size for the duct opening measurement only + Product Details Size 34"w X 6"h is the size for the duct opening measurement only