Got my new gas tank ready to install, and took a look at my original surge filter. To my surprise there is nothing inside the plastic. Shouldn't there be some type of packing in there? I was thinking of shoving in some fiberglass wadding or cotton *****. Something to keep debris out, and the fuel in. Photo attached.

 

Gauze pads and cotton *****. I've installed gauze pads first to keep the cotton ***** from entering the line.

 

I have a new one lying here so I looked for you. Yes there is foam, black, looks to be very small cell (if that makes sense). The body of the thing is full and it looks to have been put there as a long strip and folded as it went in, the hose nipples have nothing in them.
I have used a green foam lawn mower filter to put in a vent hose. I know they are oil and gas resistant and the whole point of a vent on the fuel tank is to allow air to move s-l-o-w-l-y, I reasoned the foam lawn mower filter would do just that. And it did work for me, just fine.

 

Thanks for the quick replies!