This ring for hair, is an interesting object for 3D printing. Quite easy to print through a Stereolithography and FDM 3D printers. This one can be printed without supports. It is fast to print and looks great.
For the second variation, the one without the concavity, supports are necessary on FDM printing.
Ringing visible on the black printed model, due to adaptive layer height variation… That not always work well. - Both of this models Print without supports
The author marked this model as their own original creation.