This will hold your ring while also showing it off.  There is a hole in the bottom for a magnet that let's you keep the ring nearby without having to worry about losing such a tiny but valuable thing.  I am always surprised at how well this holds my ring, I am unable to pull it off once the threads are engaged.

When the two pieces are apart simply click your ring onto the clamp piece (it's a nice satisfying click) then thread it onto the other piece.  Even before they are fully together the ring is held very well.

The uploaded design is for a ring with these dimensions (sorry, I don't know anything about ring sizing so they are simply in metric):

Inner diameter: 19.812 mm
Outer diameter: 23.749 mm
Height: 7.366 mm

And the magnet hole is for a 2x8mm cylindrical magnet.

If you would like to alter this design for another size you can do so with this link:

[https://cad.onshape.com/documents/9e60dc11f45958b0f67ce441/w/6e4c62836e7e8eecca3cc7d1/e/fa2120c768112d238948fe02](https://cad.onshape.com/documents/9e60dc11f45958b0f67ce441/w/6e4c62836e7e8eecca3cc7d1/e/fa2120c768112d238948fe02)

There are parameters for these dimensions but things might break if you get too far from the original dimensions.