Features: Optical fiber identifier is-a necessary tool for optical fiber maintenance. It is used for nondestructive optical fiber identification and can be detected anywhere in single-mode and multi-mode optical fibers. During maintenance, installation, wiring, and recovery, it is often necessary to find and separate a-particular fiber without interrupting the service. By transmitting signals of 1310nm or 1550nm band-modulation tones (270 Hz, 1 kHz, 2 kHz) into the fiber at one end, it is recognized on the circuit by an identifier, which can also indicate the light of the fiber. Identified wavelength-Range: 800-1700nm. Efficiently identifies the traffic direction and frequency-tonel (270Hz, 1KHz, 2KHz) with-audible warning. Specifications: Material:ABS Size:Approx.3x2.7x20cm/1.18x1.06x7.87inch Package Includes: 1x Fiber Tester note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thanks for your understandings.