UFC mixed martial arts television series and event in 2006
The Ultimate Fighter 4 is the fourth season of the mixed martial arts reality television series The Ultimate Fighter. It premiered on August 17, 2006, immediately after the conclusion of UFC Fight Night 6. The finale was aired on November 11, 2006. This series featured a change from the usual Ultimate Fighter format. Instead of UFC hopefuls, the cast was composed of fighters that had fought in the UFC but had yet to win a UFC title.
https://en.wikipedia.org/wiki/The_Ultimate_Fighter_4