Product review (2 stars): You get what you pay for. I didn't want ...
You get what you pay for.  I didn't want to pay $30/knob so I gave these a try.  Some work okay, but one quit after the first time I used it - I think because the range was hot the plastic softened just enough that it no longer holds the prong in the stovetop so it just spins and spins and doesn't let you adjust the setting (thankfully the range was off when this happened!).