8" x 20" or 20" x 8" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 10.5" X 22.5"] white + Product Details Size -

+ Product Details Size - 26"w X 18"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 22" x 10" OR 10" x 22" duct opening (measured at the opening)

also referred to as T-Bar or Lay-in system

+ Product Details Size – 48"w X 24"h is the size for the duct opening measurement only

ensuring compatibility with most thermostat models

8" x 20" or 20" x 8" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 10.5" X 22.5"] white + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 8" x 20" or 20" x 8" duct opening (measured at the opening), with actual outer dimensions of 10. 5" W x 22. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 7. 75" x 19. 75" x 1" Premium Airflow Efficiency High performance cube core eggcrate design allows 95% airflow efficiency, reducing energy costs and maximizing HVAC system lifespan. Durable, Rust Free Aluminum