16" X 6" 2-Way Air Supply Grille – Steel HVAC Vent Cover with Damper, Wall/Ceiling Register, White 10in diameter + Product Details Size –

+ Product Details Size – 8" x 24" or 24" x 8" is the size for the duct opening measurement only

you can watch this informative video tutorial: How to Measure Your Vent Hole Before Ordering a Grille

and with a built-in back 1/2" mesh they also protect you from annoying rodents like mice

+ Product Details Size - 18"w X 34"h is the size for the duct opening measurement only

16" X 6" 2-Way Air Supply Grille – Steel HVAC Vent Cover with Damper, Wall/Ceiling Register, White 10in diameter + Product Details Size –+ Product Details Outer dimensions: 17. 75"W x 5. 75"H fits a 16" X 4" duct opening Durable stamped steel construction ensures long lasting performance Designed for sidewall and ceiling installation with included screws Multi shutter damper with easy lever for precise airflow control Smooth powder coated white finish for a sleek look and scratch resistance + Product Description Maximize your homes airflow with this premium Air Supply Grille air supply