Ss-nit-020_v.7z.001 -

: This signifies that this is the first part of a multi-part (split) archive.

Are you getting an (like "Unexpected end of data") when trying to open it?

Since files with these naming conventions often originate from file-sharing platforms or forums, keep the following in mind:

To help you further, I can look into more specifics if you tell me:

You cannot open part .001 in isolation; it contains only a fraction of the total data.

: The official 7-Zip website offers the native tool for this format.