30" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w32h32 + Product Details Size – G12123CUBL FBA Product Details Size 25 10" Diameter

+ Product Details Size – 6" x 26" or 26" x 6" is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 18" x 32" OR 32" x 18" duct opening (measured at the opening)

With precise measurements and easy installation

including the ability to mount without removing the thermostat when using the ring base

30" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w32h32 + Product Details Size – G12123CUBL FBA Product Details Size 25 10" Diameter + Product Details Size – 6" x 26" or 26" x 6" is the size for the duct opening measurement only + Product Details Perfect Fit & Easy Sizing Designed for a 18" x 32" OR 32" x 18" duct opening (measured at the opening)