Feature: 1. High measurement accuracy and display resolution. Provide absolute optical power measurement and relative power measurement. 2. When the output power changes, it can quickly display the tracking and real-time measurement of the optical power. 3. With wide measurement range, it can provide 80dBm optical power measurement range. 4. Automatic shutdown function. Monitor and display the battery power in real time, and display a warning notification when it is low. 5. Equipped with LCD display, it iseasy to read the value. It has the function of visual fault locator function. Specification: Item Type: Optical Power Meter Material: Plastic Product Model: TL550A Measurement Range: -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: For InGaAs Accuracy: <±3% (-10dBm, 22℃) Resolution: Linearity: 0.1%, Non-linearity: 0.01dBm Working Temperature: -10℃~+50℃ Storage Temperature: -20℃~+70℃ Relative Humidity: 90% (+ 30°C) Connector: removable FC / PC SC / PC Power Supply: 2 x AA battery (battery not included) Working Time:> 120 hours (without backlight). Package List: 1 x Optical Power Meter (Battery Not Included)1 x Adapter Head1 x Storage Bag1 x Manual