10"w X 4"h 1-Way FIXED CURVED BLADE AIR SUPPLY DIFFUSER - Vent Duct Cover - Grille Register - Sidewall or Cieling - High Airflow - White 10"w X 4"h Is The Size For The Duct Opening Measurement Only, Actual Front End Outer Dimensions Are 11.75" Width X 5.75" Height - SEE BELOW IN DESCRIPTION HOW TO MEASURE A GRILLE Multi-Shutter Damper With Handle Operator - Screws Included Quality Packaging - Carefully Shrink Wrapped With Cardboard Backing To Prevent Damage In Shipment Carefully Shrink Wrapped With Cardboard Backing To Prevent Damage In Shipment Easy Unrestricted Air Flow For Your HVAC System