Product review (4 stars): Try replacing the knob first
This product appears to be an original replacement or very close to it. My wife and my dryer's timing mechanism wasn't working. We thought the timer might be faulty because the knob was spinning around without doing anything. We decided to try just replacing the knob first. When we put on the new knob the mechanism worked perfectly! The only drawback is that this knob can't take much abuse because it's made of mostly plastic. The original knob worked for a little less than 6 years, so with gentle use I would estimate the replacement should work for 5 or more years.