With a short <8m dead zone the QX40 is designed for FTTx application. It can test the length, fiber loss connector loss and other physical characteristics of fiber. it can locate events on fiber cables precisely. It is really the tool of choice for FTTx application installation and maintenance as well as for fiber R&D and producing testing. QX50 rugged design, lightweight and easy operation, as well as the low-reflection LCD and more than 10 hours battery life make it be perfect in filed testing