Product review (4 stars): They fit my stove
I have a 70's style Magic Chef Chateau gas range (the chateau means it has an upper oven).  The knob shafts are the standard 1/4" "D" size and stick out 7/16".  I found the black insert works just fine for me.  The oven knob has preprinted temperature readings and are unfortunately not positioned correctly for my oven - 100 degrees off!  There are two sets of inserts: the black is 5/8" long (sticks out 1/8" when inserted onto the knob) and the white is 7/16" long.(1/16" below when inserted)  The knobs are a little less than 2" in diameter and 1-3/8" long.