This grill matches the Cabinet Vent and is mounted into a 3 1/8 or 3 1/4 inch (80mm) hole. Installation-1.Determine location for the grill ensuring that there will not be any obstructions inside the cabinet,2.Using a hole saw, drill a 3 1/8 or 3 1/4 inch (80mm) hole in the cabinet,3. Using the grill as a template, place it in the hole and mark the 4 screw holes and pre-drill those with a small drill bit (smaller than the screws),4.Screw grill to the cabinet.