The Connector of general electronic products (Connector) and electrical accessories (Pin) are called plugs. A male connector with a rod or copper plate protruding from an ac power plug and socket in a physical way, and a female connector with a slot or concave hole. Size is a key technical requirement that relates to the safety of plug sockets and converters, and whether to meet universal interchangeability requirements to avoid false insertion. The improper size can affect user's use or production of bad contact, false insertion and other hidden dangers, light will cause the equipment to be damaged, and the weight will generate fire and electric shock.