The base inner diameter is 16. Only size adjustments down to 13-16 are possible. For sizes larger than 16, please confirm if it's possible before purchasing m(_ _)m I post videos 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, brings out human charm, smooths interpersonal relationships, and is expected to deepen the bond with a partner. ※ The main effects of plum blossom tourmaline are generally the health and mental balance adjustment, detoxification effect, and the meaning of symbolizing 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. In addition, 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 make it again without the parts, so please check before purchasing ( ´._.`) Since it is completely handmade, please purchase if you understand. ※ Please check the image properly, make a judgment, and if you have any questions or concerns, please ask before purchasing. Returns, refunds, and exchanges will not be accepted after arrival. I am handmade! Please understand. If you are looking for perfection, please purchase at a shop. (※) The price includes shipping, packaging, and handling fees. I reject bulk purchases with a discount for the shipping fee because I don't understand the meaning. (※) 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 orders, only size adjustments.