The usp_black_satn.zip file you have requested: Skins / Weapons / CS: Source USP Tactical Black - 1.34mb is not available. Perhaps try browsing all files for the game Counter-Strike: Source and upload any files you want to share or are missing. This is the only information we could locate:
Here is a simple reskin of the CSS USP pistol to black. The body has been darkened, and the clip and silencer have also. Other then that, there's really not too much to describe.