The 2 pins US Outlet Plug (A Type) is a "child-proof" type design, which fits the common socket outlet in USA, Canada, Mexico and most area in Japan. It just likes the plug of your electrical appliance to cover the socket outlet and away your child to place their fingers, toy keys or other objects into the socket outlet. It is easy to plug in the wall socket but difficult for little hands to remove. However, an adult can simply to remove the plug with just a squeeze.