30" X 12" ADJUSTABLE AIR SUPPLY DIFFUSER - HVAC Vent Duct Cover Sidewall or Ceiling d Think of the diameter as

Think of the diameter as a straight line from one end to the other

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

+ Product Details Perfect Fit & Easy Sizing - Designed for a 10" x 10" duct opening (measured at the opening)

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+ Product Details Size - 22"w X 10"h is the size for the duct opening measurement only

30" X 12" ADJUSTABLE AIR SUPPLY DIFFUSER - HVAC Vent Duct Cover Sidewall or Ceiling d Think of the diameter as+ Product Details Size 30"w X 12"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 31. 875" width X 14" height. High Quality High quality steel construction, no scuff powder coat durable finish, smooth, shiny, scratch resistant, no sharp edges, 2 recessed screw holes on each side with screws included, screws same color as vent cover, easy installation. Adjustable airflow control Adjustable airflow