30" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible With Duct 8in Universal Fit – Measures 3-7/8"

Universal Fit – Measures 3-7/8" wide x 3-1/2" high x 3" deep

+ Product Details Size – 36"w X 10"h is the size for the duct opening measurement only

+ Product Details Size - 14"w X 34"h is the size for the duct opening measurement only

+ Product Details Size – 34"w X 24"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 26" x 36" OR 36" x 26" duct opening (measured at the opening)

30" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible With Duct 8in Universal Fit – Measures 3-7/8"+ Product Details Perfect Fit & Easy Sizing Designed for a 30" x 18" OR 18" x 30" duct opening (measured at the opening), with actual outer dimensions of 32. 5" W x 20. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 29. 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