A crocodile clip (also alligator clip) is a sprung metal clip with long, serrated jaws which is used for creating a temporary electrical connection. This simple mechanical device gets its name from the resemblance of its jaws to those of an alligator or crocodile.
It is used to connect an electrical cable to a battery or some other component. Functioning much like a spring-loaded clothespin, the clip’s tapered, serrated jaws are forced together by a spring to grip an object.
When manufactured for electronics testing and evaluation, one jaw of the clip is typically permanently crimped or soldered to a wire, or is bent to form the inner tubular contact of a ~4 mm (0.16 in) female banana jack, enabling quick non-permanent connection between a circuit under test and laboratory equipment or to another electrical circuit. The clip is typically covered by a plastic shroud or “boot” to prevent accidental short-circuits.