Special overhand

[OMGWTF]

Ok this is the directly down overhand, does it have a name? (most people refer to the overhand as a right hook with a slip, but this is the proper overhand that truly comes over the top from 12 oclock to 6 oclock.

Also how do you throw this punch for optimum power? Can you get any more power out of it than what he is showing would it be more powerful with a slip?

(for me I find I get a longer range of motion and a more powerful overhand if I slip to the side Tyson style)

((Tyson slips from the waist by bending to the side, which is very unusual, most slips are either bending forward at the waist, bending one leg so you tilt to the side or rotating the hip to take your head off angle, or some combination of these slips))