  The proliferation of near-infrared (1--5 $\mu$m) photometric systems over the
last 30 years has made the comparison of photometric results difficult. In an
effort to standardize infrared filters in use, the Mauna Kea Observatories
near-infrared filter set has been promoted among instrument groups through
combined filter production runs. The characteristics of this filter set are
summarized, and some aspects of the filter wavelength definitions, the flux
density for zero magnitude, atmospheric extinction coefficients, and color
correction to above the atmosphere are discussed.
