Seems simple enough to duplicate. An old glove stretcher made of wire and sandwiched between 2 pieces of trim, glued together in a clamp. This is a great site with many ways to repurpose old found items into useful objects.
Craft show ring box 1 by Wudls on Etsy
Jewelry display. Love this. Maybe try it with embroidery hoops???
Image of A FEW OF MY FAVOURITE SMALL THINGS
Jewelry packaging pop out boxes
Ring display holds 3 rings cast cement by PityFab on Etsy, $32.00