UL power line is regulated power line commonly known as: 120V 50/60HZ divided into two core, three core wire and polarity and non polarity, the power plug copper to the United States must have a rubber sleeve; line two core line printing said line; polarity pins the zero line, foot small fire line (power line and zero line circular concave and convex surface for FireWire);

UL power cord plugs generally refer to the unfixed half of the plug. The plug with a positive contact is called a common plug, and a plug with a negative contact is called a plug. The socket generally refers to the half of the fixed (on the panel or chassis). A socket with a positive contact is called a socket, and a socket with a negative contact is called a socket.

Three eyes: fire line, ground wire, zero line.