Insulated wire is wire covered in a layer of insulating material to provide protection that will increase safety and efficiency. In addition to insulating single wires, companies can also individually insulate wires in a single bundled cable for the delivery of more complex electrical signals. Phone lines, for instance, require multiple wires, all of which need individual insulation to function correctly. Numerous manufacturers produce insulated wire products, including custom products for specific applications that may require unique components.