Features IDENTIFICATION OF DIRECTION: Correctly determine the optical fiber's direction. The left and right direction lights indicate the signal direction when an optical fiber signal is present. When the left direction light turns on, it is clear that the light EFFICIENT IDENTIFICATION: With sound alerts, the fiber identifier efficiently distinguishes between traffic direction and frequency tones (270Hz, 1KHz, and 2KHz), and inform you. 10KM MEASUREMENT DISTANCE: Built in VFL red light source can measure a distance of approximately 10KM, which is able to meet most of your Identification requirements. ABS MATERIAL: Optical fiber detector is made of premium ABS material, which is wear and scratch resistant and has a long service life. EASY CARRYING: With the optical fiber's compact design and light weight, this optical fiber identifier is portable and simple to use. Specification: Item Type: Optical Fiber Identifier Material: ABS Battery: 3.7V polymer lithium battery 802040 650mAh x 1 (shipped with built in battery) Application: Fiber optic identification Basic Parameters: Wavelength Range: 800 to 1700nm Signal Recognition Type: CW, 270Hz ± 5%, 1kHz ± 5%, 2kHz ± 5% Detector Type: Dia. 1mm InGaAs 2 pcs Adapted Fiber Type: Universal Dia. 0.25 (for bare fibers), Dia. 0.9, Dia. 2.0, Dia. 3.0 Fiber optic patch cords Signal Direction: LED indicator light for left and right direction indication Optical Power Reading Range: -40dBm to +10dBm Display Resolution: Linear Display: 0.1% Logarithmic Display: 0.01dBm Red Light Source Usage Distance: Greater than Approx. 10000m / 32808.4ft Working Temperature: -10 to +60 ℃ Storage Temperature: -25 to +70 ℃ Package List:1 x Optical Fiber Identifier1 x Manual  1 x USB Cable  1 x Storage Box Package List 1 x Optical Fiber Identifier 1 x Manual 1 x USB Cable 1 x Storage Box