30"w X 24"h Steel Return Air Grilles - Sidewall and Cieling - HVAC DUCT COVER - White 30"w X 24"h Is The Size For The Duct Opening Measurement Only, Actual Front End Outer Dimensions Are 31.75" Width X "w X 25.75" 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. Some of the best features aren't readily apparent, but you will appreciate the benefits over the period of time. This grille has a high standard of design, production and finish on all products. 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. 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. 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.