Fidget Spinner Centerpiece, V2

My prior model (thing:2080149) had a small rounded top. I have since moved to a flat disc shape on both sides, which I like better for gripping the spinner. Here are two options, with thin and medium thickness.

Note: This is for an 8x22x7 bearing, standard skateboard bearing.

Note 2: The .STL file called Bearing_Centerpiece_8mm.STL is a tighter fit for the cap.