There is a steel seal on the inner ring of the bracelet. Generally, bracelets are marked on the inner ring or the buckle of the extension buckle. Buy bracelets in regular jewelry stores, don't buy them online, to prevent the fake from being genuine. You need to keep the receipt, and you need to clean it or replace it later. It is best to buy heavy or semi-solid bracelets, which are not easy to deform when knocked down, but will deform when worn for a period of time when the weight is small.