NC Solenoid Valve: This is a normally close type electric solenoid valve, power on to open it and power off to close it. There is an arrow sign on valve showing flow direction, please follow the sign to connect pipes Zinc Alloy Solenoid Valve: The high quality zinc alloy valve body would hold a press up to 0.8Mpa and liquid temperature from -5℃ to 100℃. 3/4" BSPP (DN20) Thread Size, 20mm Flow Orifice Suitable Fluid Temperature: Electric valve is suitable for use with pipelines in water, air, gas and low viscosity non-corrosive fluid applications Installation: This solenoid valve is designed to installed indoors horizontally in a dry environment. If used outdoors, the coil part should be well protected from water Note: AC220V Input Voltage. Electric magnetic valve is better for intermittent short time work, single continuous power on time is better to be less than 30 minutes