Microprocessor-driven hand-held optical power meter featuring linear amplification technology for long-term calibration stability. With five calibrated wavelengths, 780, 850, 1300, 1310 and 1550, for accurate transmitter output power measurements. Lasts over 14 hours on a single 9V battery. Power measurement in dBm and watts Measurement Range: +23 to -50dbm Resolution: 0.05db Absolute Accuracy: within 0.2dB (5%)