8" X 4" Adjustable AIR Supply Diffuser - HVAC Vent Cover Sidewall or Ceiling - Grille Register - High Airflow - Black w12h12 + Product Details Size -

+ Product Details Size - The listed 10" diameter refers specifically to the size of the duct opening

Actual Filter Size – 17 3/4"w x 5 3/4" x 1"

+ Product Details Size – 18"w X 32"h is the size for the duct opening measurement only

Use appropriate fittings and avoid using excessive force when tightening connections

+ Product Details Size – 18" x 28" or 28" x 18" is the size for the duct opening measurement only

8" X 4" Adjustable AIR Supply Diffuser - HVAC Vent Cover Sidewall or Ceiling - Grille Register - High Airflow - Black w12h12 + Product Details Size -+ Product Details Size 8"w X 4"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 9. 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