ID this apparatus

[Tom_N]

I was fortunate to have visited the Stuttgart Porsche museum this week, where I saw a deconstructed 996 C4. The apparatus in the picture intrigued me. What is it? How does the floating ball (arrow) function?

[Tom]

Looks like the fuel level sensor that sits in the gas tank.

[audi4t]

I just replaced one like that in my toilet tank after 9 years - $8

[Tom_N]

Looks like the fuel level sensor that sits in the gas tank.

Of course, that's the fuel tank.

[CEW]

Fuel pump and fuel quantity sending unit in the tank. The ball floats and sends signal to gauge.

[Tom]

Looks like the fuel level sensor that sits in the gas tank.

Of course, that's the fuel tank.

I looked at it a few time too, thinking it looks like a fuel sender -- but what's it doing in the trunk? Finally realized the tank was cut away too....