A cable is one, two or more wires bound together, typically in a common protective jacket or sheath. The individual wires inside the jacket may be covered or insulated. This wire is usually copper because of its excellent conductivity. Cables are used to connect two or more devices such as a hard drive and a motherboard or two PCs to enable communication between them. Cables come with various connectors that focus on an area of transmission – video, data, audio, power, etc. Some cables can transfer multiple streams of data or video.