12" X 4" 3-Way Air Supply Grille – Steel HVAC Vent Cover with Damper, Wall/Ceiling Register, White Aluminum Adjustable Curved Blade + Product Details Size -

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

actual front end outer dimensions are approximately 38 5/8" width X 36 5/8" height

actual front end outer dimensions are approximately 2" wider

damper-link:hover { color: #003366

Powder-Coat Finish – Never rust

12" X 4" 3-Way Air Supply Grille – Steel HVAC Vent Cover with Damper, Wall/Ceiling Register, White Aluminum Adjustable Curved Blade + Product Details Size -+ Product Details Outer dimensions: 13. 75"W x 5. 75"H fits a 12" 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