There are several. One, the torpedo, lives in the Mediterranean and is about 45 cm long. To stun the fish it feeds on it produces a shock by using two electrical organs located on the sides of the head. Their operation is comparable to that of a real electric battery: the negative pole is facing the animal's belly, the positive one towards the back, and the discharges are directed from the belly to the back. The production of electricity is under the control of the nervous system: from here start bundles of nerves that send their terminations to the electric organs. The organs, however, run out quickly and need a rest to be able to recharge. The shock can also be felt by humans, but it is not dangerous: it has a voltage up to 50-60 volts, very little compared to the 220 volts of the domestic current. Many other fish, such as the gimnoto, or electric eel, use electric current to perceive the prey or stun it.