Product review (4 stars): No slots for burner feet.
These are sturdy and the openings are big enough for the coil plugs. I am only giving 4 stars because there are no slots or indentations for the burner "feet" So the burners don't sit level. Kinda bummed.
UPDATE: 6 months later: I still keep these on my burners all the time, I just cut a slit for the foot.