Seems like there have been a proliferation of fidget spinners lately.
I think I’ve been offered a dozen in this last month. The first time I saw one online I didn’t know what they were for, but after a little research I learned they are to help focus someone with ADD or ADHD by giving them something to do with their hands. The theory is that some people have excess energy and giving them something to fiddle with helps focus the person on the more important task.
There is a guy at my work who has several of these, and when he’s on the phone he fidgets with them and he says they work for him. No one in my family has those types of issues, however I found that my boys love messing with theirs anyway. It’s just a fun low-tech gizmo that people seem to universally like.
I think the metal ones (usually made from brass or steel) are more satisfying to use than the lighter plastic ones, but the all metal constructed spinners are much more costly. Be prepared for $20 to $50 each. Cheaper plastic ones I have seen as low as $6.