I have to keep this as it was needed before I could get a replacement. I really like the semi-elastic material the scooter is made of. Hole drilled 1.25mm off center. At a radius of 17mm, the error approaches 10%. I wouldn't even believe such mistakes are possible in modern production. Of course, when you use it, it bounces up and down, which is pretty annoying. Overall it's a good material but a bad product due to poor workmanship. If you think this doesn't bother you, the roller works.