Feature:1. Simple Operation: The fiber identifier can be tested online without changing fixtures, and is universal for single mode and multi mode2. Multi Frequency Identification: The optical fiber identifier can identify 270Hz, 1KHz, 2KHz signal frequency3. Buzzer Prompt: The handheld fiber optic identifier has buzzer sound indicate when identifying the frequency4. LED Light Display Direction: This fiber identifier can accurately identify the fiber direction which LED indicator light can show left and right5. Excellent ABS Material: The fiber optic identifier is made of high quality ABS material, has high strength, not easy to damage, sturdy and durableHow to Use:1. Press the power button to power on or off the device.2. Put the optical fiber into the adapter slot and pull down the buckle.3. When the optical signal passes through the optical fiber, the LED indicator will light up to indicate the direction of the light source, and the relative power will also be displayed on the display.4. If there is no light signal going through the fiber, the LED will light up and the LO will show.5. The fiber identifier can also detect 2KHz, 1KHz and 270Hz modulated audio.6. Press the VFL button to turn&