I need help with .001 - .070 Exentions to a game file

[travis1446]

I download this ps2 game with the 70 files all splited up with the .001 - .070 extentions at the end of these files i had also used a program called HJ split to join up all of those files to one big ps2 game the size of 3.2 gb but when i did this the big game it had no extention to the big file I have no idea what extention to use it with so i hope u can help

THank You.

[Sedulus]

use winrar to unrar the files, not HJsplit