This 1968-1979 Fresh Air Insert Knob White Arrows snuggly inserts into the center of the dash knob. The correct know had a square hole in order to rotate the controls to pe the fresh air vents.
Note: This insert fits within the rubber dash knob very tightly. Make sure know is warm prior to placing insert into knob. We suggest a little heat from a hair drier to make the job easier. DO NOT OVERHEAT.