The COSA-4055 from Viavi Solutions Inc. is a Optical Spectrum Analyzer with Wavelength Range 1260 to 1625 nm, Wavelength Resolution Readout Resolution: 0.001 nm, Wavelength Accuracy ±0.5 nm, Dynamic Range -55 to 10 dB, Sweep Time Scanning time: 4 Sec. More details for COSA-4055 can be seen below.