My grandson had the upper expander when he was 8 years old, 2 years ago. He had great results and almost no complaints. My daughter, his mom, was a little squeemish about turning the "key", but once she did it, it went just fine. He didn't have to have it all that long. Their bones are growing so fast at that age that the results are quick. (By quick, I mean several months). So much better than having a lot of teeth extracted as his mom did and then into braces for several years. He may need braces later on but should not be extensive. Best wishes.