Features: 1.The smart ring is a stylish wearable electronic product that can be connected to a smart phone through Near Field 2.Communication (NFC) to complete function execution and data sharing. 3.Designed with high water level waterproof function, it can be used without any power supply. 4.Embedded with NFC chip, it can only be connected to smart phones with NFC function.    Notice: Please allow 1-3cm deviation due to manual measurement Actual color may be slightly different from the image due to different monitor and light effect Description: Material: Stainless Steel Size:as shown Package List: 1X Ring