16" X 4" ADJUSTABLE AIR SUPPLY DIFFUSER - HVAC Vent Duct Cover Sidewall or Ceiling Aluminum Bar + Product Details Size -

+ Product Details Size - 20"w X 20"h is the size for the duct opening measurement only

or commercial environment

+ Product Details Size - 4"w X 26"h is the size for the duct opening measurement only

only measure the "hole" in the wall/duct

16" X 4" ADJUSTABLE AIR SUPPLY DIFFUSER - HVAC Vent Duct Cover Sidewall or Ceiling Aluminum Bar + Product Details Size -+ Product Details Size 16"w X 4"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 17. 875" width X 6" 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