Turn Cap made for the STREBITO screwdriver set.
This is made to come in as a tight interference fit, plan accordingly, this can done via tuning your printer tolerances or by increase the size of the model via the slicer scale.
For more information please head over to my GrabCad page https://grabcad.com/library/screw-driver-turn-cap-1
The author hasn't provided the model origin yet.