... This kind of mould(socket) applys in plastic pipe welding machines, is made of Aluminium alloy.the size is 16mm. This kind ... of mould(socket) applys in plastic pipe welding machines, which is made of Aluminium alloy, and covered with American famous ... plastic pipes from adhering when welding the pipes,by the way, we also have D20mm, D25mm, D32mm, D40mm, D50mm, D63mm,D75mm ...