KPM-35 Optical Fiber Power Meter Tester Hand Held Measuring Instrument -70 - +10dbm Item Type: Optical Power Meter Material: ABS Wavelength: 800-1700nm Measuring Range: -70 - +10dbm Optical Connector: FC + SC + 2.5mm Universal (LC Optional 1.25mm) Power Supply: 3 x AA 1.5V Alkaline Battery (Battery Not Included) Display Unit: dB/dBm/w Resolution: 0.01dB How e: (Following numbers correspond to button numbers of manual) 1-1 LED light button: click to turn on or off the lighting function 1-2 Red light button: Click constant light, then click blinking, and then click to turn off the function 2. Wavelength switching button: 7 different test wavelengths can be selected, and the selected test wavelength is displayed at the top of the screen 3. Power button: click to turn on/off the device 4. REF/db unit button Short press db unit to switch, uW/dBm/dB Long press once to enter the last cleared data, press again until the screen displays REF, reduce the current optical power and set it to the reference value, enter the relative optical power test mode, the display will display the set reference value Self-calibration: press 1 and 4 buttons at the same time to enter the calibration mode, the default value is -10, press 4 button to increase, press 2 button to decrease, press 1 button to save.