26 x 20 Return Air Grille - Sidewall and Cieling - HVAC Vent Duct Cover Diffuser - White 26 w X 20 h Is The Size For The Duct Opening Measurement Only Actual Front End Outer Dimensions Are 27.75 Width X 21.75 Height - SEE IN DESCRIPTION HOW TO MEASURE A GRILLE PROPERLY Why HVAC Premium? 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. With HVAC Premium you get an extra measure of quality that will be visible to your family members and house guests. 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. Heavy Gauge Steel. Heavier gauge than needed 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 How To Measure A Grille Overa