Fiber Optic Loopbacks feature single mode (9µm) and multimode (50µm /62.5µm) loopback plugs designed for equipment testing, self-testing, engineering, network diagnostics and measurement applications. Known also as loopback adapters, loopback cables or fiber optic loopback modules (incorporating two fiber optic connectors) these devices are typically used for testing the transmission capability and receiver sensitivity of network equipment. They are an important part of troubleshooting in laboratories and manufacturing environments. A high optical performance is achieved due to a precision ceramic ferrule.