1. 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 wide measuring range offers an 80dB optical power measurement capability, supporting both absolute and relative power measurements. 2. Accurate measurement and quick response: Ensures precise results with accuracy and a backlit LCD display. The user selfcalibration function enhances reliability. Experience fast tracking and realtime measurement of optical performance when changes occur—efficiency at its . 3. Easy battery monitoring: Monitor battery power in real time with lowpower warnings. The automatic shutoff function adds convenience. Powered by 3xAAA batteries, it delivers long battery life, making it portable and ideal for professionals on the go. 4. Usage: Press the power button and the 'dBm' button simultaneously to enter manual calibration mode (all four unit rows will be displayed). Select the calibration wavelength using '.' Press 'REF' to increase the power value by 0.05 dB each time, and 'dB/W' to decrease it by 0.05 dB.