8" X 20" Or 20" X 8" Heavy Duty Floor Grille - Fixed Blades Air Grille - Brown [Outer Dimensions: 9.75 X 21.75] 4in diameter + Product Details Perfect Fit

+ Product Details Perfect Fit & Easy Sizing - Designed for a 14" x 18" OR 18" X 14" duct opening (measured at the opening)

+ Product Details Size & Compatibility – The size of galvanized sheet metal straight floor boot is 14" X 4" X 8"

Design – This Long throat oval stack head is designed to meet new high ceiling construction

+ Product Details Size – 18"w X 24"h pleated MERV 8 filter for HVAC return filter grille - 3 Pack

8" X 20" Or 20" X 8" Heavy Duty Floor Grille - Fixed Blades Air Grille - Brown [Outer Dimensions: 9.75 X 21.75] 4in diameter + Product Details Perfect Fit+ Product Details Size 8"w X 20"h or 20" x 8" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 9. 75" width X 21. 75" height. High Quality High grade steel construction meant for high foot traffic areas. Installation Location Floor. Design Easy drop in installation Powder Coat Finish Smooth, shiny, scratch resistant, with no sharp edges. Looks like it was just waxed. Quality Packaging Carefully