Features: Six wavelength test, dynamic range up to 80dB, measurement error less than 0.2dB. 500 sets of data storage, can be viewed at any for time, with night backlight function, convenient to use. Multi-function optical power meter, optical power meter, network test, LED flashlight three functions in one. Accurately measure network line sequence, judge signal transmission, portable storage, compact and easy to carry, prevent loss. Built-in USB rechargeable battery, long battery life, design with LED light, convenient for line inspection and construction in dark environment. Specifications: Material: ABS Size: Approx. 59x98x27 mm/2.32x3.86x1.06 in Wavelength range: 700~1700nm Probe type: InGaas Frequency identification: 270Hz, 1000Hz, 2000Hz Standard wavelength: 850/1300/1310/1490/1550/1625nm Charging voltage: 5V/1A Measuring Range: 60NT: -70~+10dBm, 60NC: -50~+26dBm Type: A/B Package Includes: 1x Optical Power Meter 1x Manual 1x USB Cable 1x Lanyard note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Type A is for communication, the range is -70, +3, type B is for radio and television, the range is -50, +20. (For security, hotel, cable TV, sometimes -50B is used) Type A Test range is -70+3 Type B test range is -50+20.