Feature: 1. QUICK RESPONSE: Optical power meter works quickly and accurately, plug and play, easy to use. Has built in relative power calculation, calibration function for more convenient use. 2. EASY TO USE: Simple operation together with 50km teat range distance largely simplifies the testing and greatly improves working efficiency. 3. LONG BATTERY LIFE: Optical fiber power meter features low battery consumption, has a continuous operation for 40 hours. Suitable for outdoor use. 4. WIDE APPLICATION RANGE: 10 wavelengths and light source. 850, 980, 1270, 1300, 1310, 1490, 1550, 1577, 1625, 1650nm with SC, FC, ST adapters. Covering the majority of communication engineering maintenance needs. 5. EASY CARRYING: Comes with a small size and a lightweight as well, you can easily store and carry the LED optical fiber power meter for convenient use. Specification: Item Type: Optical Fiber Power Meter Material: ABS Red Light Source Detection Distance: Approx. 50000m / 164042ft Power Supply: Requires AAA battery x 2 (shipped without battery) Probe Range: InGaAs Wavelength Range: 850 to 1650nm Standard Wavelengths (nm): 850, 980, 1270, 1300, 1310, 1490, 1550, 1577, 1625, 1650 Display Resolution: Linear Display: 0.1% Logarithmic Display: 0.01dBm Working Temperature (℃): -10 to +60 ℃ Storage Temperature (℃): -25 to +70 ℃ Automatic Shutdown Time (min): 10 minutes Battery Continuous Working Time: Not less than 40 hours . Package List: 1 x Optical Fiber Power Meter 1 x Lanyard 1 x Manual