Back-Up Ring Kit
Back-up rings kits are made with Buna 90, FKM or Teflon. Back-up rings are used to prevent the O-ring from entering the clearance gap. When high pressures are exerted on the O-ring, its soft rubber material can be forced into the clearance gap causing the O-ring to extrude. The hard Back-up ring material will keep the O-ring material from flowing into the gap which will prevent premature failure.