Scale the model up and down as needed to achieve a tight fit for the magnet. The hole on the side opposite to the magnet slot is there to make it easier to push the magnet back out again.
The files are labelled as “clip-a-b.stl”. “a” is the width of the slot to pull the towel loop through, “b” is the radius of the center hole. Pick as needed
Included is also a general purpose hook using the same size of magnets.
The author marked this model as their own original creation.