Additional Details ------------------------------ Product description: 12"w X 8"h 1-Way FIXED CURVED BLADE AIR SUPPLY DIFFUSER - Vent Duct Cover - Grille Register - Sidewall or Cieling - High Airflow - White 12"w X 8"h Is The Size For The Duct Opening Measurement Only, Actual Front End Outer Dimensions Are 13.75" Width X 9.75" Height - SEE BELOW IN DESCRIPTION HOW TO MEASURE A GRILLE You may think of grilles and registers as a generic component of the ventilation system in your house. But they are also the most visible representation of you air system. These grilles and registers give you an extra measure of quality that are visible to your family members and house guests. High Standard Every part is hand inspected for quality before it is packaged, no exceptions. No Sharp Surface Edges. Just run your finger along the edge of the top plate and you will find a smooth finished surface. Rigid Gauge Steel. Rigid gauge built for durability and long life in mind, but still light and handy. Powder-Coat Finish - Smooth, Shiny, Scratch-Resistant, Beautiful. Looks Like It Was Just Waxed Quality Packaging - Carefully Shrink Wrapped With Cardboard Backing To Prevent Damage In Shipment Easy Unrestricted Air Flow For Your HVAC System How To Measure A Grille Overall Size: Measure the size of the air duct/drywall opening. Do not measure the overall size of the register itself, only measure the "hole" in the wall/duct. Every grille has a front end frame, that will overlap at wall joint. Total outer size of this grille is; listed size +1.75". Width vs Height The first number in a grille size, represents the width, the second number represents the height. Example: If your hole is 20" wide by 14" tall, order a 20x14. If your hole is 14" wide by 20" tall, order a 14x20.