1. Optical Power Meter Function: a). Optical power measurement: supports 850/980/1310/1490/1550/1625nm wavelength, b). Unit switching: dBm or mW/uW/nW, c). REF reference, d). Optical power frequency test: can identify light sources with 270Hz, 1KHz, and 2KHz frequencies. 2. Cable Continuity Testing: Used to detect line sequence, short circuit, open circuit, crossover, etc. of network cables, and display the results in the form of line sequence lights and the screen. 3. Red Light Function: Supports 3 modes of "constant light, slow flash, fast flash". 4. Crystal Crimp Test Function: Check whether the crystal is crimped well. Please note: the physical slightly color difference or difference, does not affect the use, please do not mind, thank you! : Product Name: Optical Power Meter Type: -916 Display: Color screen Optical power measurement: 850/980/1310/1490/1550/1625nm Lighting function: Yes Charging method: Type-C charging, 3.7V lithium battery Colour:Photo Color Material:plastic Package Contents: 1Pcs -916 Network Cable Tester 1Pcs Type-C Data Cable 1Pcs English manual Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.