SR's Wolf 4 is the fourth mod made by Harry Mass Sr. It was released on June 9, 2000. It is the first of his mods to feature a new title screen.
As with his three other SR mods, this also features 10 levels played in Episode 1, here titled Closer, in a custom EXE based on registered Wolfenstein.
An SDL port was released on October 13, 2013.