These are 8mm widths and made of the same tungsten as our other rings.
As the rings are plated be sure to be careful when cleaning up the inside of the ring. We have tested cleaning out these rings with a razor blade on the inside rather than any sanding and it does work well.
When loading onto mandrels we would suggest to add some layer between the metal and the mandrel. Perhaps some black electrical tape would work well for this.
Gold and rose gold plated tungsten is more durable than other plated colors.