... flow rate, save energy.** Stainless steel seat** Unique sealing ring, with saw-tooth sides, embedded directly into disc, bolt-free connection ... & clearance free connection, eccentric pin maintains strength of shaft, large contact area, tight for long service,good exchangeability.** Excellent sealing ... iron, aluminum alloy, S.S.DiscD.I.+ nickel plated, D.I. + nylon 11 coated, 304 and 316 S.S.SeatNBREPDM ...