30"w X 28"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 31.75"w x 29.75"h] return filter Don’t worry RFGF1212 Rigid Design Noise Free Oval to Round 90-Degree Boot

Don’t worry

+ Product Details Size – 28" x 36" or 36" x 28" is the size for the duct opening measurement only

+ Product Details Size - 26"w X 16"h X 2"d (for duct opening measurement only)

+ Product Details Size - 28"w X 30"h is the size for the duct opening measurement only

Its locking eight-tumbler mechanism and supplied key safeguard your thermostat from tampering

30"w X 28"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace Weather Resistant Air Grille with Screen Mesh [Outer Dimensions 31.75"w x 29.75"h] return filter Don’t worry RFGF1212 Rigid Design Noise Free Oval to Round 90 Degree Boot Don’t worry + Product Details Size – 28" x 36" or 36" x 28" is the size for the duct opening measurement only