This toilet seat has a mechanism which can move a kind of plastic film covering from one end to the other. When people use it, they just press on a button, and a new and clean plastic film will come out and cover the toilet seat ring, at the same time,the used film covering is destroyed by a cutter and curled up by used roller. So, it is always clean and safe for your use. It will make you free of worries when using public toilet seats.