28" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 8in diameter + Product Details Size –

+ Product Details Size – 26"w X 14"h is the size for the duct opening measurement only

+ Product Description Protect your thermostat with the durable and tamper-proof Beige Metal Thermostat Guard

+ Product Details Perfect Fit & Easy Sizing - Designed for a 16" x 24" OR 24" X 16" duct opening (measured at the opening)

+ Product Description Enhance your ventilation system with our high-quality grilles and registers

Our T bar drop ceiling grills are renowned for their exceptional 360-degree airflow capability

28" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 8in diameter + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 28" x 18" OR 18" x 28" duct opening (measured at the opening), with actual outer dimensions of 30. 5" W x 20. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 27. 75" x 17. 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