These are tiny spacer rings rings, look at all the pictures for style references. I do offer size 2mm and 3 mm custom name rings to add to your collection.
Here is the link to the 3mm ring:

   https://www.handmadelovestory.com/products/stackable-rings

 Stainless Steel is a wonderful alternative to sterling silver because it is hypo allergenic, does not rust, change color or tarnish. And because it is so durable, it can be treasured for a lifetime. It also does not cost a fortune, which is the best part! It does have a mirror shine finish so please wear with care to avoid scratching.