Bikers Gremlin Bell's 

Gremlin Bells also called Guardian Bells are meant as a guardian angel of the motorcyclist. They protect the rider on his way in the same way that travellers worship St. Christopher, the saint of travellers. The legend of the bell tells that there are evil spirits and demons on the road who want to do nothing but harm.

Probably you have heard about the hard to determine problems that arise in engines (mostly with electrical systems), these are called "Gremlins". It is said that these inexplicable mistakes are caused by evil spirits that want to belittle the rider.

The Gremlin Bell is a way to ward off these ghosts. It is said that the protector on the bell captures the ghosts in the hollow part of the bell and destroys them by the constant ringing of the bell until they get so angry that they go away and never come back. Well, not to a rider with a Gremlin Bell anymore!