I present the Ring III, this model has been designed for printing in stainless steel, or one of it's variants.
The sizing of this ring model is for a 20.1mm internal diameter, a UK U1/2 (US 10.5).
However it can be scaled up indefinitely and scaled down to have a 19mm internal diameter, a UK R1/2 (US 9).
If you would like a specific size then please send me a message or post the request below.
There are some more photos of this object and other examples of my work, both 3D printed and otherwise, on my 'Tofty' facebook page.