This read-only object reports the fractional picometer portion of an SFP module's laser wavelength, providing sub-nanometer precision for wavelength monitoring. For example, if the wavelength is 1510.01 nanometers, this object would return 10 (representing 0.01 nm), while the main wavelength object reports 1510 nm. An operator would use this fine-grained wavelength data to precisely characterize optical modules and detect potential wavelength drift in long-reach optics.