Networx(tm) Fiber Optic Loopback Cables provide a return signal for fiber optic equipment which can be using for tesing purposes and isolating any network issues. Built using high quality Corning Glass, these fiber loopback adapter cables will offer consistent performance time and time again. All the Networx(tm) fiber optic patch cables are backed by a lifetime warranty. We also offer custom built Fiber Optic Assemblies. If you don't see what you need contact us with your requirements.