I wanted a fidget spinner that uses glass marbles for the weights (because marbles look cool!) but I just couldn't find one.  So I did what any 3D printing enthusiast would do and designed my own.  Marbles aren't of uniform size but this model should accept anywhere from ~14-16.5mm marbles or so.  I've printed a zillion of these things (as demonstrated in the picture) and they were a big hit in my son's 4th grade class.  They're "the cool fidget spinners"...  These kids have *loads* of fidget spinners but this is the one they call covet.

Since the marbles stick out above and below the spinner more than usual I've also designed some caps to go along with it.  They are press fit and should be seriously tight (no glue required).  Both male and female caps are included.

I designed this with kids in mind so it should fit in small hands.  Just be careful with little ones and small parts!