I designed this t-handle for allen keys to make using the ball end more comfortable and allow for applying more torque. 

The part shown in the photos was printed on a Mk3S in Prusament carmine red PETG. I recommend 25% gyroid infill and ~5 wall loops for strength.

Slicer settings: 0.2mm layer, 25% gyroid infill, 5 wall loops, printed standing up on the hex base without support on a textured plate.

I have previously also uploaded this model to Printables. Find me @nxls_3097256