I want to talk to you about harmonic balancers. Here I have an ATI harmonic balancer or a damper. This part is designed to control the harmonics within your engine. In truth they do not actually balance an engine, but rather they absorb and remove unwanted vibration due to torsional twisting of the crankshaft. So in effect, they could be called vibration dampeners and are frequently referred to as dampeners.
You might also be interested in a post where John talked about XS power batteries.