A handpiece driven by a small low-voltage motor (in the back half
of the handpiece) that runs at max. 30.000 rpm at 24 V, power is 150 W.
Used for drilling, milling and grinding, also for setting stones in juwels.
For the same purpose there are also stationary motors with a flexible shaft and a small handpiece.
Some goldsmiths prefer the stationary type, some the other. The shown electrical handpiece is a little bigger but less stiff to handle.