Connectors facilitate conductivity using a wide variety of methods. Barrel connectors do not require crimping and feature two open ends to accommodate a pair of wires. Screw connectors use a screw to establish conductivity. Different types of screw connectors act as terminals to provide secure, quick and reversible connections. Depending on the screw connector design, the wire may be wrapped under the screw head or fastened to metal. Butt connectors feature open ends for simple crimping and a built-in wire stop to ensure accurate positioning. Transition connectors create splices between differently sized conductors and function similarly to reducer barrel connectors, with each end designed to accommodate different wires. Pigtail connectors can accommodate three wires in one insulated unit for additional connection configurations. Closed-end and spring connectors facilitate quick connections through simple twisting or crimping action. Spring connectors feature a live inner spring to maintain a strong connection.