Product review (4 stars): the adjustment inserts fit are uni-directional
I saw a lot of complaints that the adjustment insterts won't fit - i had the same problem until noticing that one end of each insert is veeery slightly beveled to be inserted.  you can barely notice this but unless you insert that end into the knob, it won't slide in.  in fact even inserting the correct end it is still a bit difficult and you have to work it around and push pretty hard - but they do fit.

also as mentioned these are apparently not "universal" because all the inserts are for the same size half moon post - they fit my stove perfectly but apparently from comments there are other size posts on other stoves.

oh yeah and people had complained that the sticker showing off position doesn't stick - the sticker has a backing - also not readily apparent - you need to peel off the backing to expose the sticky side and then it will stick

all in all, not a very intuitive product - but once you figure it out, it worked great for me -- and at an unbeatable price