I just copy/pasted this from another thread I posted in, it gets the point across lol.
Once you hit level 50 and unlock a Specialization, you only need to progress ten more levels to "complete" that Specialization.
Example. Hit 50, choose Wetwork. You have 10 levels to gain with unique unlocks at each level. The first 9 grant you different permutations including armor, weapon skins, emblems, visors, and eventually, at the 10th level, a unique game changing perk.
So by the end of it all, you'll be SR 60. So on and so forth for each respective specialization.
zxXStunnaXxz - Yondaime H4X Teen Gohan was the best by far... Then came Saiyaman. Oh Akira Toriyama... WHY?!