18"W X 36"H [Duct Opening] ALUMINUM RETURN GRILLE - EASY AIR FLOW - LINEAR BAR GRILLES [OUTER DIMENSIONS: 19.875"W X 37.875"H] Filter Grille 6" x 6" - opening

6" x 6" - opening (vent hole - Neck Size) dimension - actual size is approx 2" wider

+ Product Details Size - 32"w X 6"h X 2"d (for duct opening measurement only)

High diffusion induction rates result in rapid temperature and velocity equalization of the mixed air mass well above the zone of occupancy

12"w X 2"h Is The Size For The Duct Opening Measurement Only

18"W X 36"H [Duct Opening] ALUMINUM RETURN GRILLE - EASY AIR FLOW - LINEAR BAR GRILLES [OUTER DIMENSIONS: 19.875"W X 37.875"H] Filter Grille 6" x 6" - opening+ Product Details Size 18"w X 36"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 19. 875" width X 37. 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