8" [Duct Opening] Round Ceiling Diffuser - Easy Air Flow - HVAC Vent Duct Cover [White] - [Total Outer Dimensions: 12"] 18in diameter + Product Details Size –

+ Product Details Size – 36"w X 12"h is the size for the duct opening measurement only

Actual Filter Size – 23 3/4"w x 31 3/4" x 1"

Pre-flared ends with nuts are for simple and easy installation

actual front end outer dimensions are approximately 32 5/8" width X 38 5/8" height

actual front end outer dimensions are approximately 16 5/8" width X 36 5/8" height

8" [Duct Opening] Round Ceiling Diffuser - Easy Air Flow - HVAC Vent Duct Cover [White] - [Total Outer Dimensions: 12"] 18in diameter + Product Details Size –+ Product Details Size The listed 8" diameter refers specifically to the size of the duct opening. However, please note that the total outer dimensions of the grille measure 12" in diameter. Design Heavier gauge than needed, built for durability and long life in mind, but still light and handy. (Screws included). Airflow Easy unrestricted airflow for your HVAC system. Powder Coat Finish Smooth, shiny, scratch resistant, beautiful. Looks like it was