28" x 36" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 2-Way + Product Details Size -

+ Product Details Size - 14"w X 4"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 16

providing a perfect fit for most standard thermostats

Secure Locking Mechanism – Features a permanently attached eight-tumbler lock with a supplied key for added security

Filter Size - 11

28" x 36" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 2-Way + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 28" x 36" OR 36" x 28" duct opening (measured at the opening), with actual outer dimensions of 30. 5" W x 38. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 27. 75" x 35. 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