This was designed so that I could print it off and give it to some people at work on my Project called “PICS”.  

The middle circle has a 30mm x 1mm high gap on both sides.  I designed a separate piece to print off that would fit there. I printed off that circle at 29.75mm x 1 in order to fit properly and then I just glued it in place.  As you can also see, I did a color change halfway on this print.  This works particularly well for ring fidgets because you can turn it around and get the rotating colors.  

Print it off with supports on the build plate in order to have it print correctly with the center gap.  

I know these models exist in plenty of places but I designed this from scratch with Fusion 360.  There is 1 mm gap between each ring and each ring's width is 3.5mm.  (besides the middle one which is about 34mm wide).  It is 20mm high. I printed this off with a Prusa Mini with the new Input Shaping firmware and it took about 2 hours. I used a 15% infill. 

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Also, in case you are wondering how I printed off the middle piece that says PICS.  It was actually two different models.  I printed the word PICS in blue filament 2 layers at .2mm each layer.  Then I changed the filament and printed off the grey with a large Z-Hop so that it wouldn't crash into the already existing filament. That second print had the exact gap of the letters PICS.  

I have a link to the Tinkercad project where I created the circle pieces if you want to start by duplicating that project. https://www.tinkercad.com/things/8eeVV0n2vSd 

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Lastly, in case you are wondering I used the Polymaker PLA Pro filament so that it will hopefully last longer than regular PLA filament. The colors with Blue and Grey. 
https://www.amazon.com/gp/product/B099K2ZBMC