... . S, 17-4pHS, aluminum bronze and monel.resistant NBR, Viton, high temperature Viton, Hypalon, Silicon rubber PTFE Bushing: Glass backed PTFEover EPDM ... . S, 17-4pHS, aluminum bronze and monel.resistant NBR, Viton, high temperature Viton, Hypalon, Silicon rubber PTFE Bushing: Glass backed PTFEover EPDM ...