The connector and the electrical appliance plug (Pin) of general electronic products are called plugs. Household AC power plugs and sockets have rod-shaped or copper-shaped protruding male connectors that are physically inserted into female connector-type power sockets with slots or recesses. The size is an important technical requirement related to the safe use of plugs, sockets and converters, and whether they meet the universal interchangeability requirements to avoid mis-insertion. Unqualified size will affect the user's use or cause hidden dangers such as poor contact and mis-insertion, ranging from damage to the equipment, and serious to fire and electric shock accidents.