28" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter return filter Actual Filter Size – 11

Actual Filter Size – 11 3/4"w x 19 3/4" x 1"

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

These grilles and registers give you an extra measure of quality that are visible to your family members and house guests

+ Product Details Outer dimensions: 15

28" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter return filter Actual Filter Size – 11+ 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