Feature:1. Plug and Play: This optical power meter has no need to wait for warm up, plug and play, very convenient to use!2. Accurate Measurement: This meter features accurate measurement, relative power calculation, and calibration function.3. Long Service Span: This is a low battery consumption meter that it can realize 100 hours of continuous operation.4. Scope of Application: This meter can detect 6 standard wavelengths and light sources. 850, 1300, 1310, 1490, 1550, 1625. Covering most requirements of communication engineering maintenance.5. Easy Carrying: Comes with a compact size and a light weight as well, you can easily take this meter with you to help with your work.Specification:Item Type: Optical Power MeterMode: TL537AMaterial: ABSPower Measurement Range: - 70 to +10dBm (at 1550nm)Standard Wavelength: 850 1300 1310 1490 1550 1625Joint Type: for InGaAsAccuracy: 0.35dB 1nwOperating Wavelength: 800 to 1700nmContinuous Working Time: 100hStandby Time: About 230hPower Supply: AAA battery x 2 required (shipped without battery).Package List:1 x Optical Power Meter1 x Storage Box 1 x Manual