Features Accurate measurement, high measurement accuracy and backlit LCD display resolution, with user self‑calibration function. Quick response and measurement. When the output power changes, it can display fast tracking and real‑time measurement of optical power. Wide measurement range, can provide 80dB optical power measurement range, absolute optical power measurement and relative power measurement. Six calibration wavelengths: 850nm, 1300nm, 1310nm, 1490nm, 1550nm and 1625nm. Easy to use, real‑time monitoring and display of battery power When the battery power is low, a warning notification will be displayed and automatic shutdown function. Specification: Item Type: Optical Tester Material: Plastic Product Model: TL510 Measurement Range dBm: -70~+10 dBm (the actual best measurement range is -65 ~ 0dBm) Wavelength Range (nm): 800-1650 Calibration Wavelength: 850nm, 1300nm, 1310nm, 1490nm, 1550nm, 1625nm Detector: InGaAs Accuracy: Resolution: Linearity: 0.1%, Non-linearity: 0.01dBm Working Temperature: -10℃-+50℃ Storage Temperature: -20℃~+70℃ Relative Humidity: 90% (+ 30°C) Connector: Removable for FC / PC SC / PC Power Supply: 3xAAA batteries (delivered without batteries) Working Time:> 120 hours (without backlight) How to Use: 1. Press the power button and the dBm button at the same time, the instrument enters manual calibration mode (all four rows of units are displayed at this time) 2. Select the calibration wavelength with λ, press REF to increase by 0.05dB each time, and dB/W to decrease the power value by 0.05dB 3. Short press the power button to save the calibration data 4. Press the power button and the REF button at the same time to exit the calibration mode. PackageList: 1 x Optical Power Meter(Battery Not Included) 1 x Adapter Head 1 x Storage Bag 1 x Manual Package List 1 x Optical Power Meter(Battery Not Included) 1 x Adapter Head 1 x Storage Bag 1 x Manual