Glyd ring is a two-way sealing ring which is composed of a rubber O-ring and a PTFE ring. It has the characteristics of low friction, almost no creep, low starting force, and high pressure resistance. It is to produce a higher initial contact stress on the sealing surface through its own deformation to prevent the leakage of non-pressure liquid. Under working pressure, the Glyd ring can squeeze the square sealing ring to the maximum extent through the elastic deformation of the O-ring, so that it is close to the sealing surface, and produce a higher additional contact stress that increases with the pressure of the pressure liquid, thereby effectively preventing the leakage of the pressure liquid.