- Large measuring range: covers 850 nm, 1300 nm, 1310 nm, 1490 nm, 1550 nm and 1625 nm, providing a comprehensive optical power measurement range. The device supports an optical power measurement range of 80 dB with both absolute optical power measurement and relative power measurement. - Accurate measurement and quick response: high accuracy with a backlit LCD display. The user calibration function increases reliability. Offers fast tracking and real-time measurement of optical performance as changes occur. - Easy battery monitoring: real-time battery status and low power consumption warnings. Automatic shut-off for convenience. Powered by 3x AAA batteries, delivering long battery life and portability for professionals on the go. - Use: 1) Press the power button and the dBm button simultaneously to switch to manual calibration mode (all four unit rows are displayed). 2) Select the calibration wavelength with lambda. 3) Press REF to increase the power value by 0.05 dB each time, and dB/W to decrease the power value by 0.05 dB. - Applications: suitable for fiber optic lab calibration of transmitters across 850–1625 nm, field installation and maintenance to verify optical power at key wavelengths, and real-time monitoring of optical performance during system changes.