All right. Anti-bacterial zinc oxide is added to the silica gel of the sealing ring, which can effectively prevent the growth of harmful substances such as bacteria after long-term use. The rubber ring at the bottom of the thermostatic kettle is waterproof material, which mainly plays a sealing role. As far as the silica gel used in the health pot is concerned, it is mostly food grade, of course, the premise is the products produced by regular businesses.