It's just a fidget spinner but has draft all the way around and in the center hole. Here are my casting notes. 

• I cast it as a spilt pattern in old Petrobond. 
• No gating, just a Sprue/Feeder and one end and a Feeder at the other. 
• Sand was just packed down by the heal of my hand and any lose sand was blown out. 
• Poured in Pewter @ 290c which was too hot (should have been 250-275c). 
• Cut off the feeders, sanded these faces and the edge. 
• Chucked it into the tumbler to see what I had. 
• Carefully sanding the center hold and press fit the 608ZZ bearing (the center is tapered from 27 to 26mm). 

The pics shows the mold, casting still in sand, and the casting removed from the sand for reference as well as the final spinner.  

All the detail came out, including the fine raised and recessed text. You can see the sand grain but no major defects. Free from shrinkage (was worried about the metal being too hot). A bit of flashing and the parting line was easy to sand off.  One defect, is that I dilled a hole for the alignment pins but did not fill them. You can see in the top right where one of these were.  

I cast it in pewter as Al would be too light for this. Zinc / CU alloys would also work great.

So if anyone wants to play along, here is the patterns (one is the whole model, the other are the two halves).