Question about .rar

I understand the whole .rar and .part01 extensions for a rar'ed file. But when I started using newsgroups, I noticed some files also have this:

5783 - File 01 of 19 - yEnc "5783.part01.rar" 1457664 bytes
5782 - File 22 of 22 - yEnc "5782.vol3+4.PAR2" 1553364 bytes

I don't understand what the .vol3+4.PAR2 file is.

I read the PAR and PAR2 pinned topic, so I'm guessing it's a fill in for one of the corrupted .rar files?

yes

http://www.slyck.com/ng.php?page=6

Sweet

awesome