Inspired from a purchasable hook which did not fit my needs (to big) i designed a similar hook for rails. The hook does not come of easily from the rail, so it is perfect for hanging clothes or other things on the rail. You can customize this hook with OpenSCAD.

Printing:

material: PETG works best for me and is recommended

no supports

infill: 100%

perimeters: 5

I made some STL-Files for rail diameters 20, 25 and 32 millimeters, you can change the diameter for both sides, the length, the width and the thickness with the customizer of OpenSCAD.