Question about parts in Watermaker

[Farenhigh]

Hello guys, i am wondering what are these parts name?

The black one goes to the water tank and the white one goes into the host base. When the water tank is installed on the host base, the white part push the black part up allow water to flow through.

Here is an overview of the water maker.

 

[Erich]

It is a valve. It is closed when the tank is loose. So you can fill the tank at the sink. Installing the tank onto the base opens the valve.