This read-only integer object reports the laser wavelength, in nanometers, of the SFP transceiver installed at the remote end of the link. An administrator compares this against the local transceiver's wavelength to confirm both ends of a fiber link are using compatible optics for the distance and fiber type involved. For example, seeing a mismatch between the local and remote reported wavelengths would explain why a supposedly matched pair of optics is not establishing a stable link.