12" X 12" Outdoor Return Air Grille – For Outdoor Use - HVAC Vent Duct Cover Diffuser – [1.0mm Polished Aluminum] [Outer Dimensions: 13.75w X 13.75h] Grilles + Product Details Size -

+ Product Details Size - 5" Diameter is the size for the duct opening measurement only

Round-neck-to-square-face construction results in 360 degree air diffusion pattern similar to a full round diffuser

+ Product Details Size – 18" x 22" or 22" x 18" is the size for the duct opening measurement only

+ Product Details Size - 34"w X 12"h X 2"d (for duct opening measurement only)

Aluminum Garage Door Air Vent Grille Register - With Damper Control Lever For Winter & Summer Settings - With Insect Net Prevent Guard [17

12" X 12" Outdoor Return Air Grille – For Outdoor Use - HVAC Vent Duct Cover Diffuser – [1.0mm Polished Aluminum] [Outer Dimensions: 13.75w X 13.75h] Grilles + Product Details Size -12" X 12"h Is The Size For The Duct Opening Measurement Only, Actual Front End Outer Dimensions Are 13. 75 Width X 13. 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