This closed end connector allows you to join several wires at the same time. This is especially useful in applications where resilience against vibration is particularly important. They provide a way to make a simple connection for uses in electrical wiring. Wire connectors of this type are sometimes known as crimp connectors, because crimping the insert helps to hold the connection in place. The nylon covering acts as insulation for the copper insert. The tin plating on the insert helps provide protection from deterioration.