Optical Fiber Recognition Instrument: Features red light and LED lights to support efficient line measurement and easy operation. Capable of identifying three signal frequencies: 270Hz, 1kHz, and 2kHz, with audible buzzer alert during frequency detection. Four-in-one universal adapter fits 0.25, 0.9, 2.0, and 3.0mm fibers for convenient in-line testing without changing fixtures. Compatible with both single-mode and multi-mode fibers, allowing detection at any point along the fiber. Equipped with high-brightness LED lighting for reliable visibility during inspections and installations in low-light environments. Fiber detection range up to 10km. Powered by 2 AAA batteries (not included). Press the test switch to automatically display measurement data. Product Name: Fiber Optic Recognition Instrument (Red, All-in-One) Compatible Fiber Types: Universal 0.25mm (bare fiber), 0.9mm, 2.0mm, 3.0mm fiber optic jumpers Wavelength Identification Range: 8001700nm Signal Frequencies Detected: CW, 270Hz 5%, 1kHz 5%, 2kHz 5% Power Measurement Accuracy: +10dBm to -30dBm (continuous wave), +10dBm to -25dBm (modulated signal) Signal Direction Detection: Indicator light display Detector Type: 1mm InGaAs Red Light Test Wavelength: 650nm 10nm Red Light Output Power: 10mW Audio Prompt: Yes Color: Black Material: Plastic Package Contents: 1 x Fiber Optic Identifier Note: The package includes only the items listed above. Other accessories are not included. Due to lighting reflections and differences in display settings, the color in the image may slightly differ from the actual product. Measurement error allowance: 13cm.