The base inner diameter is 16. Size adjustments down to 13-16 are possible. For sizes larger than 16, please confirm availability before purchasing m(_ _)m Videos are posted on Instagram ▶︎ ichigohime__ Please read the profile before purchasing. ※ The meaning of pink agate is considered to be a power stone that is effective for improving love luck and relationships. It brings kindness and peace to the heart, enhances human charm, smooths interpersonal relationships, and is expected to deepen bonds with partners. ※ The main effects of plum blossom tourmaline generally include the health and mental balance adjustment, detoxification effects, and the symbolic meanings of patience and good luck that are expected of tourmaline, but these are the effects as a power stone, and there is no scientific basis in modern medicine. Also, as is associated with the shape of the plum blossom, it is said to have the effect of encouraging the courage and effort to overcome difficulties. I do not support metal allergies, but if there is stone stock, I may be able to remake it without the parts, so please check before purchasing ( ´._.`) Since it is completely handmade, please purchase if you understand. ※ Please check the images carefully, make your own judgment, and ask any questions or concerns before purchasing. Returns, refunds, and exchanges are not accepted after arrival. I am handmade! Please understand. If you are looking for perfection, please purchase from a shop. (※) The price includes shipping, packaging, and handling fees. I reject bulk purchases with a discount on the shipping fee because it doesn't make sense. (※) If you want a discount or a discount for bulk purchases, please leave a comment. m(_ _)m If there is no comment, it will be rejected. Please also read the profile (♡ᴗ͈ˬᴗ͈) I do not accept custom orders, only size adjustments.