A plug is a device used to connect electrical equipment to a power source. It typically consists of metal prongs that fit into a corresponding socket, allowing electricity to flow. Plugs come in various shapes and sizes, depending on the country and the type of device being powered. Common examples include the Type A and Type B plugs used in North America. In addition to electrical plugs, the term can also refer to connectors in other contexts, such as audio or video equipment. For instance, a 3.5mm audio plug connects headphones to devices like smartphones, enabling sound transmission.