The OSA-500 Series from Viavi Solutions Inc. is a Optical Spectrum Analyzer with Wavelength Range 1250 to 1650 nm, Wavelength Resolution Readout Resolution: 0.001 nm, Wavelength Accuracy ± 0.01 nm, Dynamic Range -70 to 23 dB, Sweep Time Scanning time: 1 to 5 sec. More details for OSA-500 Series can be seen below.