Plugs are devices used to connect electrical appliances to a power source. They typically consist of a plastic or metal casing with metal prongs that fit into an electrical outlet. Plugs come in various shapes and sizes, depending on the country and the type of electrical system in use. Common types include Type A and Type B plugs, which are widely used in North America. In addition to electrical plugs, the term "plug" can also refer to items used in other contexts, such as ear plugs that block sound or drain plugs that seal openings in sinks. Each type of plug serves a specific purpose, making them essential in everyday life.