34" x 14" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible With Duct 12in Round-neck-to-square-face construction results in 360

Round-neck-to-square-face construction results in 360 degree air diffusion pattern similar to a full round diffuser

+ Product Details Size – 20"w X 14"h is the size for the duct opening measurement only

Adjustable airflow control - by rotating the middle disk

Installing the plaster frame is effortless – secure it into your sheetrock

+ Product Details Size - 30"w X 20"h is the size for the duct opening measurement only

34" x 14" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible With Duct 12in Round-neck-to-square-face construction results in 360+ Product Details Perfect Fit & Easy Sizing Designed for a 34" x 14" Or 14" x 34" duct opening (measured at the opening), with actual outer dimensions of 36. 5" W x 16. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 33. 75" x 13. 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