34" x 28" Cube Core Eggcrate Return Air Filter Grille for 1" Filter return grille + Product Details Size -

+ Product Details Size - 18"w X 14"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 14" x 8" or 8" x 14" duct opening (measured at the opening)

+ Product Details Size - 30"w X 12"h X 2"d (for duct opening measurement only)

Insulation – A thick blanket of fiberglass insulation provides you with an R-Value of 8

Air Flow – Ensure a quiet and smooth HVAC system with noise-free components

34" x 28" Cube Core Eggcrate Return Air Filter Grille for 1" Filter return grille + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 34" x 28" Or 28" x 34" duct opening (measured at the opening), with actual outer dimensions of 36. 5" W x 30. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 33. 75" x 27. 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