Product review (3 stars): but I'm not sure it was even necessary because the fit is very near perfect anyway. I have not had to replace a ...
They look as nearly identical to the original you could not tell the difference. However, the all plastic construction means after exposure to heat and possibly oils, they break at the base where the torsion forces the opening apart. I have purchased three sets of these , never lasting more than a few months until I decided to try reinforcing the base. I purchased "Size 13/32" (10.5 mm), Oetiker Stepless Ear Clamps, Single Ear Hose Clamps (25 Pack)" for $7.99 here on Amazon and slipped them onto the base before installing. I used a clamp wrench to pinch them tight, but I'm not sure it was even necessary because the fit is very near perfect anyway. I have not had to replace a single knob since.