I pick out all the stones I use. I wrap each ring by hand. I love making jewelry, and that shows in each piece I make. My rings are not adjustable. Each ring is made for the size shown. The inclusion of copper in the rings often raises concerns about the metal composition. The base metals are copper and brass. The brass outweighs the copper to the point that the copper doesn't affect most people. Then these rings, for instance, are silver-plated over the base metal. They are solely plated; therefore, avoid wearing them in the shower or while swimming, and ensure they are removed prior to sleeping. I also have a bulk option for resellers. You can have one each of all twelve sizes, 4 - 15. The order also ships for free for $50.00. This item is the 13th size option that's marked 4 - 15 for $50.00. Once more, if you have any questions, please let me know.