The goods that are regularly sold in the store are marked with the identification label of the National Testing Center and the formal unified sales list to Ang. Product supervision code, inspection number, article number and metal content name are attached to the label. According to the product inspection number on the label, you can go to the appraisal unit for verification. The appraisal unit must be designated by the state, and the specific authoritative testing institution is Fang. The websites of the appraisal unit and testing organization are all in the product label. You can check. I hope it works for you!