ML2DGG is the EOS Aura Microwave Limb Sounder (MLS) product containing geophysical diagnostic quantities pertaining directly to the standard geophysical data products, generally on a similar (or identical) grid, and at different spectral ranges. The data version is 4.2. Data coverage is from August 8, 2004 to current. Spatial coverage is near-global (-82 degrees to +82 degrees latitude), with each profile spaced 1.5 degrees or ~165 km along the orbit track (roughly 15 orbits per day). Vertical resolution varies between species and typically ranges from 3 - 6 km. Users of the ML2DGG data product should read the EOS MLS Level 2 Version 4 Quality Document for more information. The data are stored in the version 5 EOS Hierarchical Data Format (HDF-EOS5), which is based on the version 5 Hierarchical Data Format, or HDF-5. Each file contain swaths objects for each diagnostics measurement. Each swath has a set of data and geolocation fields, swath attributes, and metadata.