This seal is a combination of a PTFE slip ring and an energising O-ring.It is produced with an interference fit which together with the squeeze of the O-ring ensures a good sealing effect even at low pressure. At highter systems pressures, the O-ring is energised by the fluid,pushing the slip ring against the sealing face with increased force.We produce a wide range of PTFE piston & rod rings for a variety of standard piston bore & rod dimensions.Advantages.Lubrication not required.No stick-slip effect when staring for smooth operation.High wear resistance ensures long service life.Installation grooves acc.to ISO7425/1,ISO7425/2.No adhesive effect to the mating surface during long period of inactivity or storage