12"w X 6"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 13.75"w x 7.75"h] flat stamped steel Actual Filter Size – 17

Actual Filter Size – 17 3/4"w x 11 3/4" x 1"

+ Product Details Size – 20"w X 24"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 36 5/8" width X 28 5/8" height

Actual Filter Size – 33 3/4"w x 11 3/4" x 1"

4" X 10" Brass Victorian Floor Register Grille - Modern Contempo Decorative Grate - HVAC Vent Duct Cover - Brass Plated

12"w X 6"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 13.75"w x 7.75"h] flat stamped steel Actual Filter Size – 17+ Product Details Size 12"w X 6"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 13. 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