Hi,
this is a filament spool shelf. The rods are IKEA RÄCKA. You need to print the 20mm and the 17mm because the rod is adjustable and has different diameters.The rings can be used to take the rod in place by a screw. I suggest to print 3 parts (2 20mm and 1 17mm) to avoid bending of the rod.
I used PETG with 0.2 layer and 25% infill.
The author hasn't provided the model origin yet.