Fiber Loopback Patchcord is also called optical loopback adapter Or Fiber Loopback Module, is designed to provide a media of return patch for a fiber optic signal, used for fiber optic testing applications or network restorations. Opelink offer various types of Fiber Loopback Module, 7+ years of Fiber Optic Product experience, high-quality and cost-effective, welcome to inquire.