... .Only produce mould 2.describe:union ball valve 3.type:single,double,thread,butterfly,brass ball 4.material: ppr, pvc, ... than 15 years experience about making double ball valve moulds.union ball valve has seven parts.We can make ... can provide various of single/double Union valves, check valves, membrane valves, bottom valves, gate valves, locking valves, deflation valves, IBC valve, three way valve, ...