Abstract: There is disclosed a medical or dental hand-piece element comprising a coupling mechanism for a detachable connection of the hand-piece element to a drive unit, a tool receptacle that is or can be connected to the hand-piece element, and a drive element for transmitting a driving movement from the drive unit to the tool receptacle so that the tool receptacle can be set into a working movement, wherein the drive element comprises at least one rotatable shaft, and a generator for converting mechanical energy into electric energy, wherein the generator can be driven by the at least one rotatable shaft of the drive element.