20"W X 16"H [Duct Opening] ALUMINUM RETURN GRILLE - Easy Air Flow - Linear Bar Grilles [Outer Dimensions: 21.875"W X 17.875"H] flat stamped steel then you'll need a 14-inch

then you'll need a 14-inch round vent

with actual outer dimensions of 36

making installation a breeze

also referred to as T-Bar or Lay-in system

20"W X 16"H [Duct Opening] ALUMINUM RETURN GRILLE - Easy Air Flow - Linear Bar Grilles [Outer Dimensions: 21.875"W X 17.875"H] flat stamped steel then you'll need a 14-inch+ Product Details Size 20"w X 16"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 21. 875" width X 17. 875" height. High Quality High quality aluminum with counter sunk screw holes (screws included) and no sharp edges. Design Unrestricted airflow For Your HVAC system noise free components no vibrating louvers etc. Powder Coat Finish Smooth, shiny, scratch resistant, beautiful. Looks like it was