Lightweight optical reflectometer for field use by Extralink. Introducing the Extralink OTDR Fiber Optic Fault Locator, the best solution for fast and accurate identification of faults in fiber optic networks.  This powerful device uses Optical Time Domain Reflectometry (OTDR) technology to send a pulse of light through an optical fiber and measure the reflected signal. It then analyzes the data to indicate the location and severity of any problems, such as breaks, bends or loss of signal strength.