Other Gasketing Materials Polyester Foam Low Density Cured foam made up of a mixture of closed and open cells that offers good insulating qualities. RP8500 Polyether Foam Low Density Open cell foam that is highly flexible and offers good recovery. RP8500E Velcro Hook and Loop (High Technology Hook) FRB Flame Barrier Provides very high flammability and ignitability resistance. Works well as an electrical insulator. Flame Barrier FRB Series (FRB-NT, FRB-NC, FRB-WT, FRB-BK)