28"w X 36"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 29.75"w x 37.75"h] 2-Way Deflection + Product Details Size -

+ Product Details Size - 20"w X 30"h is the size for the duct opening measurement only

also referred to as T-Bar or Lay-in system

with actual outer dimensions of 8

+ Product Details Perfect Fit & Easy Sizing - Designed for a 12" x 14" or 14" x 12" duct opening (measured at the opening)

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

28"w X 36"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 29.75"w x 37.75"h] 2-Way Deflection + Product Details Size -+ Product Details Size 28"w X 36"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 29. 75" Width X 37. 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