32" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Return Grille + Product Details Size –

+ Product Details Size – 26"w X 14"h is the size for the duct opening measurement only

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

+ Product Details Size – 29"w X 22"h is the size for the duct opening measurement only

Ideal for Walls & Ceilings: Designed for seamless installation in standard 20" X 12" duct openings

ISO Supply Diffusers perform efficiently with air loadings of 6 to 30 air changes per hour (based on 10 ft

32" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Return Grille + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 32" x 18" OR 18" x 32" duct opening (measured at the opening), with actual outer dimensions of 34. 5" W x 20. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 31. 75" x 17. 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