... .resistant NBR, Viton, high temperature Viton, Hypalon, Silicon rubber PTFE Bushing: Glass backed PTFEover EPDM, PTFE over NBR, Neoprene Disc: Ni ... .resistant NBR, Viton, high temperature Viton, Hypalon, Silicon rubber PTFE Bushing: Glass backed PTFEover EPDM, PTFE over NBR, Neoprene.