Typically, a four-way solenoid valve is used to operate the double-acting cylinder. Mainly, there are five pipe connecting port, four-way solenoid valve, has become a place 2 1 inlet, 2 outlet, outlet. Because it is always closed, the exhaust port is one of the four direction any functionality. A double latch solenoid has two coils inside, it is possible to perform switching of the valve by energizing the coil in one of them. Is not that the valve is switched to form self-holding, even if the power outage after energizing time.