The base inner diameter is 16. Only size down from inner diameter 13-16 is 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. ※ Kunzite's stone meanings include "unconditional love," "infinite love," "purity," and "lovely." This stone, with its elegant pink color, is called the "stone of love" and is believed to nurture deep affection and compassion for others, and to heal the wounds of past relationships. It is also said to have a healing effect that calms emotional fluctuations and soothes the heart, smoothing relationships and bringing a generous heart. I do not accommodate metal allergies, but if I have the stone in stock, I may be able to remake it without the metal parts, so please check before purchasing ( ´._.`) As it is completely handmade, please understand and purchase. ※ 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.