Product review (5 stars): Perfect Fit
This timer knob fit my dryer perfectly.  It is identical to the original knob that came with the dryer. Not sure why the other review said the pointer was off. The 688865 knob does in fact point in the correct direction so all the dryer cycles work correctly. I had to use a little WD-40 to get the knob to slide on.
It's a very tight fit as it should be.