b.ring Smart Ring Dedicated Size Kit Sizes 7-12 New, Unused Amazon Regular Price: ¥550 [b.ring Dedicated Size Kit] You can check your ring size from US sizes 7 to 11. [Check Size Before Purchase] If you don't know your size when purchasing a b.ring smart ring, check it with this ring sizer. [Contents] Size kit (*This product does not include the smart ring itself)