18" x 34" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 8in diameter actual front end outer dimensions

actual front end outer dimensions are approximately 36 5/8" width X 38 5/8" height

For 8" Round Duct Opening - Spiral or Flex

+ Product Description The Clear Plastic Thermostat Guard provides reliable protection and security for your thermostat while ensuring optimal functionality

During summer

+ Product Details Size – 22"w X 16"h is the size for the duct opening measurement only

18" x 34" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 8in diameter actual front end outer dimensions+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 34" OR 34" x 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 36. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 17. 75" x 33. 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