12"w X 12"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Brown [Outer Dimensions 13.75"w x 13.75"h] Compatible With Duct 10in actual front end outer dimensions

actual front end outer dimensions are approximately 18 5/8" width X 38 5/8" height

+ Product Spec Sheet Aluminum Return Filter Grille Spec Sheet

For 6" Round Duct Opening - Spiral or Flex

+ Product Details Size - 28"w X 20"h is the size for the duct opening measurement only

75" Width X 21

12"w X 12"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Brown [Outer Dimensions 13.75"w x 13.75"h] Compatible With Duct 10in actual front end outer dimensions+ Product Details Size 12"w X 12"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 13. 75" Width X 13. 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