... BS 10 Table E4. Disc: Grey iron, Ductile iron, with or without EPDM5. Seat: Stainless steel, Brass/Bronze etc6. ... : Lever, Gearbox operate, Electric actuator, Pneumatic operator, Opening indicator, With limit switch, Others.8. Type: Non rising stem, Rising ... steelDisc Grey iron, Ductile iron, Carbon steel, Stainless steel, with or without EPDMSeatEPDM / NBR / VITON / PTFEStemStainless steel, Brass ...