8"w X 10"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 9.75"w x 11.75"h] Fixed Blades with Damper + Product Details Size -

+ Product Details Size - 14"w X 30"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 26" x 14" OR 14" x 26" duct opening (measured at the opening)

Designed to seamlessly integrate with T-Bar vent covers in drop ceiling setups

Actual Filter Size – 15 3/4"w x 27 3/4" x 1"

Width vs Height:

8"w X 10"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 9.75"w x 11.75"h] Fixed Blades with Damper + Product Details Size -+ Product Details Size 8"w X 10"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 9. 75" Width X 11. 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