Inside tank

[Msgrodz]

Anyone know what this is? I found it inside the tank when a piece of the grommet fell inside. I grabbed the grommet but then thought what is this?

 

[weendoggy]

Looks like the vapor vent valve, located on the upper R/S.

 

[Mattstang04]

It clips on the end of the fuel filler neck that sticks into the side on the tank. Just pushes on. Likely feel off while moving/ taking tank.