18" X 4" ADJUSTABLE AIR SUPPLY DIFFUSER - HVAC Vent Duct Cover Sidewall or Ceiling Aluminum Bar The process is intuitive: simply

The process is intuitive: simply select the appropriate ceiling square for your grill

actual front end outer dimensions are approximately 10 5/8" width X 26 5/8" height

high-impact plastic

Actual Filter Size – 33 3/4"w x 13 3/4" x 1"

The first number in a grille size

18" X 4" ADJUSTABLE AIR SUPPLY DIFFUSER - HVAC Vent Duct Cover Sidewall or Ceiling Aluminum Bar The process is intuitive: simply+ Product Details Size 18"w X 4"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 19. 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