1、[Cables Maintenance] The pen visual fault locator is a device specifically designed for the design and maintenance of optical cables and lines. 2、[Visually Search] Pen visual fault locator also is used to locate cables and defects on cables and visually search for fiber breaks and use defective optical cables. 3、[Non Contact Connection] Visual fault locator red light pen is non contact connection, non destructive optical fiber and transmitter end face, output power is not affected by voltage fluctuations. 4、[Energy Saving] This VFL visual fault locator is energy saving and the output distance is 10km and wide for daily maintenance use. 5、[Easy to Carry] Small size, light weight, easy to carry at the same time can be stable output power. This VFL red light pen is a good tool for fiber testing.