Our Fiber Optic D4 Connectors are single-fiber connectors that feature a threaded, keyed body for repeatability and intermateability. The D4's design also reduces complexity and assembly time. The Fiber Optic D4 Connector's threaded mounting system provides a strong, secure connection and is popular for telecommunications and datacom fiber optic applications. The design of the Fiber Optic D4 Connector is similar to that of the FC connector, except that the D4 has a smaller ferrule and a longer coupling nut. In addition to D4 Connectors, we can provide fiber optic small form factor and standard size connectors for all of your termination needs. These include both epoxy-style and quick-termination style fiber optic connectors. Terminated fiber optic pigtails and patchcords are also available.