The electric rays are a group of rays, flattened cartilaginous fish with enlarged pectoral fins, comprising the order Torpediniformes. They are known for being capable of producing an electric discharge, ranging from as little as 8 volts up to 220 volts depending on species, used to stun prey and for defense. There are 69 species in four families. Perhaps the best known members are those of the genus Torpedo, also called crampfish and numbfish, after which the device called a torpedo is named. The name comes from the Latin torpere, to be stiffened or paralyzed, referring to the effect on someone who handles or steps on a living electric ray. Torpedo rays are excellent swimmers. Their disk-shaped bodies allow them to remain suspended in the water or roam with minimal swimming effort.