20" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 6" Round Duct Pipe this thermostat guard is compatible

this thermostat guard is compatible with most standard thermostat models

Actual Filter Size – 17 3/4"w x 31 3/4" x 1"

with actual outer dimensions of 20

+ Product Details Size - 20"w X 32"h is the size for the duct opening measurement only

20" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 6" Round Duct Pipe this thermostat guard is compatible+ Product Details Perfect Fit & Easy Sizing Designed for a 20" x 6" OR 6" x 20" duct opening (measured at the opening), with actual outer dimensions of 22. 5" W x 8. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 19. 75" x 5. 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 Made