SMLVL is a ‘companion’ to SMUH3. It provides easy handling of short offset refraction as is (or was) commonly done to refine near surface velocity models.
This is one of my hobby horses I guess. I firmly believe that the near surface has been neglected in favour of fancy processing modules that do not deliver all that they promise. Near surface investigation is a cheap and valuable tool that should be widely used on all projects. (But that is just my opinion).
SMLVL, like SMUH3 has the ability to encapsulate data and results so that everything is available for future reference rather than looking for a bunch of files and documents that have been scattered to the four winds.
And like SMUH3 it is very configurable so that you can produce a display that you want instead of the rather antiseptic plots delivered by the usual contractor software.
Details here:
https://seismatters.com/SMLVL.html