A wire connector is a fastener used to make a strong, low-impedance connection between two or more Electrical Wires in an electrical box. Not only are they made from flame-retardant materials, wire connectors also prevent wires from contacting one another or contacting exposed metal surfaces, both of which could cause a dangerous failure or short circuit. Wire connectors come in a wide array of shapes, sizes, and types. Their exterior cover is most commonly made from insulating plastic, though the connective pieces are tapered, coiled, metal springs or interior grooves that thread directly onto the wires, holding them securely in place. When the connector links the wires, it does so by twisting onto the end of the wires, drawing them into the metal spring and tightening them together within the spring. The Electrical Power is maintained by the wire-to-wire contact with the metal spring.