Leak-proof sealing ring for thermos bottles. The Sigg Gasket Set is the ideal replacement for the H&C and H&C One closures from Sigg. Since the robust drinking bottle has a long lifespan, it is possible that the ring seal may lose its effectiveness sooner and needs to be replaced. With the rubber seal, the reliable leak-proof performance of the H&C screw cap can be quickly and easily restored. The replacement seal is, of course, BPA-free and contains no harmful substances, including phthalates or estrogen-active substances.