The base inner diameter is 16. Only size down from inner diameter 13-16 is possible. If you want a size 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. ※ Milky Rose Quartz is a stone that combines the love and healing effects of Rose Quartz with the maternal, stabilizing, and purifying effects of Milky Quartz. Specifically, it is said to be effective for emotional stability, improvement of relationships, promotion of self-awareness, and healing of mind and body, and is especially recommended for women, those who want to have more emotional space, and those seeking harmony in a new environment. I do not support 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 ( ´._.`) Please understand that these are completely handmade. ※ 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. (※) The price includes shipping, packaging, and handling fees. I reject bulk purchases with a discount for 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, I will reject it. Please also read the profile (♡ᴗ͈ˬᴗ͈) I do not accept custom orders, only size adjustments.