26" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Fixed Blades Actual Filter Size – 29

Actual Filter Size – 29 3/4"w x 11 3/4" x 1"

4" X 14" Is The Size For The Duct Opening (floor/vent hole) Measurement Only

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

actual front end outer dimensions are approximately 30 5/8" width X 38 5/8" height

26" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Fixed Blades Actual Filter Size – 29+ Product Details Perfect Fit & Easy Sizing Designed for a 26" x 12" OR 12" x 26" duct opening (measured at the opening), with actual outer dimensions of 28. 5" W x 14. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 25. 75" x 11. 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