Nylock flange nuts. I like my 14v impact gun because I’ve found that the 18v guns tend to back out studs at the worst possible moments. Sometimes it lacks the grunt to loosen nuts after a run. Pulsing the trigger with the gun at random slight angles and pulling at the wheel will usually get the nuts off. If not, out come the ratchet. I’ve never thought about torque or gone back over them manually. My only loose wheel was because we forgot to tighten the nuts at all.