... .Seat : EPDM , PTFE , NBR , VITON . 4.Stem : Carbon Steel , Stainless SteelDesign standard: API609 , BS5155 , MSS-67-1995Face to face : API598Tubing ... lever , Gear box , Pneumatic apparatus , electronic apparatus , Fire-proof butterfly valve .2.Butterfly check valve, Grooved end butterfly ... butterfly valve.etc. handle lever soft-sealed carbon steel or stainless steel high-performance butterfly valve