Wire cap connectors are used to fasten two or more electrical conductors together. They are a type of electrical connector. Wire cap connectors are available in a variety of sizes and shapes and are typically made from plastic, with a tapered, conducting coiled metal insert that threads onto the wires to hold the wires secure. When the connector is twisted onto the stripped ends of the wires, they are drawn into the metal insert. The electrical continuity is maintained by both the direct wire to wire contact and by the metal insert. Wire cap connectors are intended to be installed by hand only, and may include molded grooves or blades intended to assist in hand installation. Hex tips or hex-like wings are commonly molded into higher-quality connectors that allow them to be installed with a common nut driver.