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 +1.5" inches. Width vs Height?The first number in a grille size, represents the width, the second number represents the height. Example: If your hole is 10" wide by 6" tall, order a 20x14. If your hole is 10" wide by 6" tall, order a 10x6. Easy Unrestricted Air Flow For Your HVAC System Carefully shrink wrapped with cardboard backing to prevent damage in shipment Return Grille designed for removing air in residential buildings, offices, kitchen, bathrooms or other air conditioning systems and can be installed on ceilings and walls DECOAIRCON offers a big range of different products to fit your needs. And we also offer products in different colors to best match your beautiful home. DECOAIRCON is committed to selling high-quality, high-performance, and popular ventilation products. In order to meet the needs of the majority of ventilation product customers, DECOAIRCON constantly introduces new products with new ideas, providing better and better service. Our products include air vents, vent hoses, and more products, waiting for your exploration. Return Grille designed for removing air in residential buildings, offices, kitchen, bathrooms or other air conditioning systems and can be installed on ceilings and walls