After supplied with the bicycle dynamo with plastic head for about a year by was (rubbed), a new was needed. This one, with metal head, I have now already fitted in three bikes and the first is now two years to run. The exchange was a problem, the dynamo running. The sound is ok, the contact pressure of the tire is excellent. It delivers good performance, each existing luminaires (including the 2-LED Philips, but also discounters lights) are very bright.