10" x 16" or 16" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 12.5" X 18.5"] Return padding: 20px CL 34 12B 35 Product Details Size 6 Extruded Aluminum Ceiling

padding: 20px

+ Product Details Size – 26"w X 36"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 15

+ Product Details Size – 12" x 24" or 24" x 12" is the size for the duct opening measurement only

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

10" x 16" or 16" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Aluminum White [Outer Dimensions: 12.5" X 18.5"] Return padding: 20px CL 34 12B 35 Product Details Size 6 Extruded Aluminum Ceiling padding: 20px + Product Details Size – 26"w X 36"h is the size for the duct opening measurement only