18" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w34h34 + Product Details Perfect Fit Condensate Pump Accessories RG1620AL High Quality High quality

+ Product Details Perfect Fit & Easy Sizing - Designed for a 36" x 26" OR 26" x 36" duct opening (measured at the opening)

order a 20x14

+ Product Details Perfect Fit & Easy Sizing - Designed for a 22" x 30" OR 30" x 22" duct opening (measured at the opening)

+ Product Details Size - 36"w X 24"h X 2"d (for duct opening measurement only)

+ Product Details Size – 10"w X 26"h is the size for the duct opening measurement only

18" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w34h34 + Product Details Perfect Fit Condensate Pump Accessories RG1620AL High Quality High quality + Product Details Perfect Fit & Easy Sizing Designed for a 36" x 26" OR 26" x 36" duct opening (measured at the opening) order a 20x14