With a 650nm visible fiber diode, Pen type Visual Fiber Locator YW-H410B can be operated in either continuous-wave mode or pulse mode. Being an essential and excellent tool for the installation, construction and maintenance for the optical fiber network, YW-H410B can test the breaks, bends, cracking and some other faults in fibres. It is widely used in communication, telecommunication, scientific reaserch, construction and so on. YW-H410B also festures rugged metal case and portable size, which can be easy to take and use.