The designerThese beautiful rings with the Ultimaker robot on them were designed and contributed by Peggy Bannenberg. They're quite quick to print, and look really good in silver PLA.Check out Peggy's website, because she makes beautiful jewelry:http://www.peggybannenberg.nl/Ring sizesThe sizes range from 16.5 mm (size 1) to 21.5 mm (size 11).