the ring size is about 1.8 mm, it's UV unwraped that mean you can change the texure or add them easily, so if you are looking for a good topology ring model then you are in the right place, you can use it in any kind of project.
if you need any other format just tel me and I will do that for free
please don't hesitate to tell me if you want any adjustment to the ring and I will do all my best.
best regards.