Backup rings prevent FFKM O-ring extrusion in high-pressure applications by supporting the O-ring against clearance gaps. Materials include PTFE, PEEK, and filled thermoplastics selected for strength and chemical resistance. Single backup rings install on the low-pressure side for uni-directional pressure. Dual backup rings support both sides for pressure reversals. Proper backup ring... https://globalsealstech.com/ffkm-seals/