Any help to understand this Klein screwdriver?

[qqzj]

I bought this screwdriver because I really like the adjustable length shank. And it exceeded my expectation. I thought there are only two lengths to choose from. Instead, there are four. That is pretty good. The shank/blade wobbles a little, which is not perfect, but I guess it is expected and tolerable? My question, however, is about a line in the instruction

"Spin cap for optimal and precise control"

I tried it and the tip won't spin when I turn the knob/cap at the bottom of the handle. Am I missing something? Further, if I manage to make the tip turn when I turn the handle, when is this feature useful? Thanks!

 

[qqzj]

Does it mean that if I push hard on the top of the spin cap, the handle can still spin? So it is kind of like the way precision screwdriver works? I guess that must be it. Sorry for the question then.

 

[LigouriRd]

If you are applying force to the end handle cap, like to prevent cam-out of Phillips screws, the handle can be rotated independently from the cap. The video on Klein's website for the product shows this at 37s.
...oops I responded after you answered your own question.

 

[darkzero]

The spinning cap is useful to me for small screwdrivers, like Wihas for example, when I worked in electronics repair or related at home or wherever. But I can't imagine it would be useful on a full size screwdriver. Then again I've never used a big screwdriver with a spinning cap nor have I ever seen one in person.

 

[KnurledNut]

The spinning bit carousel design credit goes to MegaPro.