8" x 8" ADJUSTABLE AIR SUPPLY DIFFUSER - HVAC Vent Duct Cover Sidewall or Ceiling 18" Diameter Actual Filter Size – 11

Actual Filter Size – 11 3/4"w x 19 3/4" x 1"

+ Product Details Size – 20"w X 18"h is the size for the duct opening measurement only

Actual Filter Size – 15 3/4"w x 33 3/4" x 1"

875" width X 11

Actual Filter Size – 9 3/4"w x 21 3/4" x 1"

8" x 8" ADJUSTABLE AIR SUPPLY DIFFUSER - HVAC Vent Duct Cover Sidewall or Ceiling 18" Diameter Actual Filter Size – 11+ Product Details Size 8"w X 8"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 9. 875" width X 10" 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