Wearable devices, such as smart bracelet, crafts bracelet, wrist band U disk (Wearable U disk), plastic band watches all the rage. Such wearable products, many of them using silica gel as a raw material. Advantages of silica gel as follows: 1. excellent elasticity, smooth feel comfortable; 2. environmental non-toxic, no skin sensitization, in line with ISO-10993 medical certification; 3. Hardness optional, providing hardness of 10 ~ 90A different materials to suit different product requirements.