This is a 3 port boost control valve/solenoid.
The valve operates at 30Hz, it is designed for 12V systems.
This allows most aftermarket ECUs (including Speeduino) to control the boost level of your turbo charged setup.
This kit includes the valve and 2 pin mini-timer connector, crimps seals and boot.
The valve can be wired anyway, polarity is not important.
The valve is plumbed in as per the diagram image.