This is a DC12V independent control four-way solenoid valve, which has an inlet and four air outlets, you can individually control the outlet of each outlet, so the outlet can be used alone can also be used with four. It will give your project a great convenience. Outlet and inlet diameter are 8mm. The length of the solenoid valve is about 80mm, height about 48mm, can be used in many DIY projects which can save a lot of space. Solenoid valve on both sides of a fixed hole to facilitate fixed. Each outlet has a separate wire to control. It depends on you about how to use it.