12"w X 8"h ADJUSTABLE AIR SUPPLY DIFFUSER - HVAC Vent Duct Cover Sidewall or Cieling - Grille Register - High Airflow - White [Outer Dimesions: 13.875" Width X 10" Height] 12"w X 8"h Is The Size For The Duct Opening Measurement Only, Actual Front End Outer Dimensions Are 13.875" Width X 10" Height - SEE BELOW IN DESCRIPTION HOW TO MEASURE A GRILLE Multi-Shutter Damper With Easy Handle Operator Gives You Full Control Over Airflow Direction & Amount of Airflow - Can Also Be Shut Completely Full 190 Degrees Control of Air Direction Vertically & Horizontally Carefully Shrink Wrapped With Cardboard Backing To Prevent Damage In Shipment - Screws Included Easy Unrestricted Air Flow For Your HVAC System