What is this?

[MochaDuck]

Can anyone guess what this is?View attachment 1704164

A purfume bottle lid?

 

[CarpCharacin]

A purfume bottle lid?

No.

 

[SueT]

a filter to....something?

 

[CarpCharacin]

a filter to....something?

It's not a filter, but that's getting closer.

 

[SueT]

does it go into a water line?

 

[CarpCharacin]

does it go into a water line?

No, but it does go into an air line.

 

[duluthralphie]

A check valve

 

[CarpCharacin]

A check valve

Correct! It goes into an aquarium air line to prevent water from getting siphoned out if the air pump stops working.

 

[CarpCharacin]

Now I need to look for something that is harder to guess

 

[Meg-in-MT]

Can anyone guess what this is?View attachment 1704164

Fuel filter?