Factory OE knob for your additional heater.
While this looks almost exactly like the A/C fan switch, it is a bit different. The surround piece with the numbers on it is a larger diameter and does not fit in the A/C switch bezel on the dash. To use this in the A/C fan position, you will need to swap the original surround piece to the new knob. Also note that this knob comes with an adapter peg so it can be used as a male knob or female knob as your switch requires.