I designed this Challenge Coin Holder to sit on a desk and display your challenge coin, without the holder really being seen when looking strait at it.
The edge of the coin rests on the small bottom lip and sits at about a 30 degree angle.
Sorry I don't have a picture with the coin on it, i made it for a friend and forgot to get a pict when i gave it to him.
The attached STL file is designed to fit a 44mm coin just perfect.
You can easily scale this model in your slicer program to fit any size coin by taking the diameter of your coin and dividing it by 44 to get the perfect size (so if your coin is 50mm, just divide 50 by 44 and you get 1.36, so scale the print to 1.36 and print..
No supports needed..

Creality

Ender 3 Pro

No

.16

25