Unbelievably the factory supplied knobs had a plastic film around them to show spark and flame settings. When the broiler was on the heat caused the film to pucker. Still useable but not nice. Then the internal tip at the end of the knob cracked. Initially, I repaired it with electrical tape. But that was only a short term fix. Getting a proper knob was the answer. Wow, I should have done this years ago! We are so happy now. These knobs should have been supplied in the beginning. Thank you AppliancePartsPros.com.