An alligator clip is a terminal that resembles a crocodile mouth for temporary circuit connection. When used outside the need to cover the insulating sleeve, the material is generally pure copper, iron nickel, iron galvanized, iron copper or stainless steel. First invented in 1908 by the United States Mueller Electric Miller Electric Co., Ltd. and subsequently applied in the automotive, telecommunications, electronics, medical and other industries, and developed a variety of styles, belonging to a test tool accessories. The alligator clip used in the battery recently is quoted at 2.50 yuan/PCS in Changzhou, Jiangsu.