18" x 20" or 20" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Copper Coil-Insulated Line Set Seamless Installation: Designed to fit

Seamless Installation: Designed to fit seamlessly into a 24 by 24 inch opening

+ Product Details Size - 14"w X 36"h is the size for the duct opening measurement only

+ Product Details Size – 26" x 30" or 30" x 26" is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 14" x 22" OR 22" X 14" duct opening (measured at the opening)

Ideal for Walls & Ceilings: Designed for seamless installation in standard 16" X 12" duct openings

18" x 20" or 20" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Copper Coil-Insulated Line Set Seamless Installation: Designed to fit+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 20" OR 20" x 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 22. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 17. 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