The model is a replica of an original in-molded one  (The white one on the picture which belonged to a prism set for bike wheels)
So primarily this is for mounting a prism to spokes. A 2mm wide spoke can fit between the legs of the rivet tightly.
Beside of this you can use anywhere where it fits.

Dimensions:
Head diameter: 10mm
Leg height: 10mm
Total height: 11mm
Hole to fit: ~6mm

Printing suggestions:
Material: PETG  (I used Prusament Galaxy black)
Orientation: To be the rivet able to handle the stress, it's head should be perpendicular to the bed and legs should be parallel with the bed and the legs' flat side should be also perpendicular to the bed. This requires support but that part is not visible anyway.
If you try with PLA this is the only way to work and even with these suggestions you can use the rivet once or twice before it breaks. I tried. 
With PETG printing it with the flat side of the head oriented to the bed can also work but I did not tried. 
Settings: Nozzle 0.15mm structural, default settings in prusa slicer. 
Support from bed and brim are needed for the orientation I suggested above. In case of the rivet's head is on the bed with flat side, no support or brim are needed but the “hook” part of the item can be weaker because of overhangs.

Filament needed: <0.5g
Print time: 4mins