6"w X 20"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 7.75"w x 21.75"h] Filter Grille + Product Details Perfect Fit

+ Product Details Perfect Fit & Easy Sizing - Designed for a 26" x 36" OR 36" x 26" duct opening (measured at the opening)

actual front end outer dimensions are approximately 26 5/8" width X 38 5/8" height -

+ Product Spec Sheet Extruded Aluminum Ceiling Diffuser Spec Sheet

+ Product Details Size – 24" x 24" is the size for the duct opening measurement only

+ Product Details Size – 30"w X 30"h is the size for the duct opening measurement only

6"w X 20"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 7.75"w x 21.75"h] Filter Grille + Product Details Perfect Fit+ Product Details Size 6"w X 20"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 7. 75" Width X 21. 75" Height Weather and Pest Proof These louvers are especially designed to prevent water from entering your home, and with a built in back 1 2" mesh they also protect you from annoying rodents like mice, rats, birds, and squirrels High Quality Aluminum The premium durable aluminum will never rust and it will never wear