18" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w22h22 this air supply register is

this air supply register is ideal for sidewall and ceiling applications

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

and then smoothly drop in the grill

75"H – fits a 20" X 4" duct opening

+ Product Details Size - 36"w X 32"h is the size for the duct opening measurement only

18" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w22h22 this air supply register is+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 16" OR 16" X 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 18. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 17. 75" x 15. 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