Product review (3 stars): factory replacement part, finally found it...but
super expensive for these little things...appreciate being able to order then, but it seems like price gouging for knobs that shouldn't come off and break to begin with...I have the AC units these go to in several apartments, and several of the knobs have come off/cracked.  These should be free or close to it!  Shipping was high too when you get used to paying Prime rates.