Product review (4 stars): Replacement Pot Lid Knob
Knob fit well once I got it on the pot lid.  The nut fits in a slot in the knob to keep it from turning while you tighten the screw. However the nut can fall out of the slotted housing and it is kind of tough to get it back in place.  This said, it was still a good buy and cheaper than replacing my wife's favorite pot.