I made this so I could more easily watch youtube while doing dishes :P and am uploading the files so you can customize it to your liking. Hook is designed to slip over a 12mm diameter rod. To complete this build you will need a "MagicMount" magnet from Scosche. Allot of the Scosche products use this magnet assembly and clip different things on the back but make sure the back is screwed on (see pictures). The "surface" mount does not have screws. Mine came from Walmart for $11.99 but you may find a better deal online. Hardware is included with the magnet. 

I am posting 2 versions, one with the hook and rounded corners (intended for use as is), and the other with just the backing and sharp corners (for customizing). I recommend rounding the corners to avoid damaging the rubber part.
For maximum compatibility there are 3 types of each version. stl step and f3d (Fusion 360)

If you print the hook version I strongly recommend reinforcing the middle of the hook as prints are weak along layer lines. I used 80% infill from 3.2mm to 16.2mm with 20% infill everywhere else.

When you make your own versions be sure to share them with the community.
Have fun designing!