U type butterfly valve Material:s.s c.s DN:2"~48". Disc ... Butterfly Valve. Seat: EPDM, high temperature EPDM, food grade EPDM, NBR, abrasive c)Shaft: 416S. Sand316S. S, 17-4pHS, aluminum bronze ... Type Butterfly Valve. Seat: EPDM, high temperature EPDM, food grade EPDM, NBR, abrasive Shaft: 416S. Sand316S. S, 17-4pHS, aluminum bronze ... PTFEover EPDM, PTFE over NBR, Neoprene. U type butterfly valve