16"w X 6"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 17.75"w x 7.75"h] 1-Way 75"H – fits a 12"

75"H – fits a 12" X 4" duct opening

+ Product Details Size - 8"w X 30"h is the size for the duct opening measurement only

+ Product Details Size – 20"w X 16"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 14 5/8" width X 20 5/8" height

Actual Filter Size – 13 3/4"w x 29 3/4" x 1"

16"w X 6"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 17.75"w x 7.75"h] 1-Way 75"H – fits a 12"+ Product Details Size 16"w X 6"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 17. 75" Width X 7. 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