Our company produces the valve are all made of alloy steel or stainless steel forging, ... . 1,It is rising stem structure with balance stem.2,Valve and bonnet,gate and seat is metal to metal.3 ... ,Between stem and bonnet have back seal structure, so that valve with pressure to replace packing stem.4,Metal to metal ... .Nom bore:1 13/16"-4 1/16" Plate gate valve