The base inner diameter is 16. Size adjustments are only possible for sizes 13-16. For sizes larger than 16, please confirm availability before purchasing m(_ _)m Size: 8mm ※ Rare Shungite bracelet! There are no plans for future restocks. Shungite is a natural mineral found primarily in the Karelia region of Russia, and it is expected to have several effects. The main effects include the absorption of electromagnetic waves (EMF), purification, antioxidant properties, and improved natural healing ability. I post videos on Instagram ▶︎ ichigohime__ Please read the profile before purchasing. Not compatible with metal allergies ( ´._.`) As this is completely handmade, please understand and purchase. ※ Please check the images carefully and make your own judgment. If you have any questions or concerns, please ask before purchasing. Returns, refunds, and exchanges are not accepted after arrival. I am a handmade seller! Please understand. If you are looking for perfection, please purchase from a shop. (※) Price includes shipping, packaging, and handling fees. (※) Discounts are not offered during time sales. If you would like a regular discount or a discount for multiple purchases, please leave a comment. Requests without a comment will be rejected. Please also read the profile (♡ᴗ͈ˬᴗ͈) I do not accept custom orders, only size adjustments.