Searching for gas-in tube replacements

I have the challenger IV style kegs with the vinyl gas in tubes. One leaks and needs replaced. I searched around and it appears the stainless ones are too big. However, all the places I found that sell the gas-in tubes online list these vinyl ones as discontinued. Anyone know where I can find some?

I know that they're available because my LHBS guy offered to get me some when looking for the big beer-out gasket. After a quick search, try looking for part KE64 and Dip Tube Gas, Challenger.

Good luck,
Wild

Four of my kegs are that style and I had trouble finding them as well. I bought some used ones a while back but that particular place doesn't have them anymore. It looks like this store still carries them though.

EDIT: I'm not sure if they come with O-rings. The plastic ones use a different type of ring than the stainless ones do. The ones that the stainless tubes use might work, but I got the right kind with the ones I ordered from the other store. The correct rings are circular but have squared edges whereas the regular O-rings you normally see are rounded like doughnuts (if that makes any sense). There is a good possibility that McMaster-Carr carries them but I'd have no idea what to look for.

...but why do we need a gas-in tube?

I don't think the posts will seal properly without something under them, and the tube lip is where the base of the poppets rest.