16" x 30" or 30" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 12in diameter By simply measuring the width

By simply measuring the width or the length of the vent

Actual Front End Outer Dimensions Are 14" Width X 5" Height - SEE IN DESCRIPTION HOW TO MEASURE A GRILLE

these heavy-duty louvers are ideal for use in attics

+ Product Details Size - 36"w X 6"h is the size for the duct opening measurement only

Actual Filter Size – 24 3/4"w x 35 3/4" x 1"

16" x 30" or 30" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 12in diameter By simply measuring the width+ Product Details Perfect Fit & Easy Sizing Designed for a 16" x 30" OR 30" X 16" duct opening (measured at the opening), with actual outer dimensions of 18. 5" W x 32. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 15. 75" x 29. 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