18"W X 18"H [Duct Opening] ALUMINUM RETURN GRILLE - EASY AIR FLOW - LINEAR BAR GRILLES [OUTER DIMENSIONS: 19.875"W X 19.875"H] 8in diameter Ideal for Walls & Ceilings:

Ideal for Walls & Ceilings: Designed for seamless installation in standard 16" X 4" duct openings

Adjustable airflow control – Adjustable airflow control: The system allows users to customize the amount of air supply

Actual Filter Size – 27 3/4"w x 31 3/4" x 1"

Its smooth

Actual Filter Size – 19 3/4"w x 29 3/4" x 1"

18"W X 18"H [Duct Opening] ALUMINUM RETURN GRILLE - EASY AIR FLOW - LINEAR BAR GRILLES [OUTER DIMENSIONS: 19.875"W X 19.875"H] 8in diameter Ideal for Walls & Ceilings:+ Product Details Size 18"w X 18"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 19. 875" width X 19. 875" height. High Quality High quality aluminum with counter sunk screw holes (screws included) and no sharp edges. Design Unrestricted airflow For Your HVAC system noise free components no vibrating louvers etc. Powder Coat Finish Smooth, shiny, scratch resistant, beautiful. Looks like it was