Sorry I had a 8mm seized bolt, I bought your impact T40 thinking it would be tough enough BUT NO?
It started to distort with only only medium pressure. I bought a T40 STAHLWILLE socket it fitted better and no distortion at all
These are really rugged I am impressed. I went thru a couple of regular T40 hex bit.
one broke in half the other went flying, I was using them outdoors so I never could find it.
But these are a 3/8" drive!!