Closed end connectors are crimp-able for a quick, inexpensive, easy and permanent electrical connection of two or more wires. The outer insulating shell of the connector is made from nylon and houses a small tinned aluminium or copper barrel. You simply insert your wires all the way into the closed end connector and crimp around the barrel using any standard wire crimpers. The connectors are able to connect multiple wires together and work well on both stranded and solid core wire. The maximum voltage rating for closed end connectors is 300 volts.