1)body:WCB/stainless steel
2)bonnet:WCB/stainless steel


3)flap:WCB/stainless steel


4)stem:stainless steel
5)seal face:STL
6)packing:Fexiable graphite

7)gasket:stainless steel+flexiable graphite

8)apply water/gas/oil/nitric acid/acetric acid