Hi Charlie, a valid concern, but the hose and valve assembly packs are available, typically as used, serviceable units; I've had several NOS units in this previous (link below) listing, but didn't think to keep any and sold them all as a package.
https://www.yenko.net/forum/showthre...=162951&page=2
I'll look for another assembly to enable the use of these cans and add it to this listing when I do and you can reach back out then.
I suspect you may also be able to search for some in the used market like Craigslist of FB Marketplace or even yard sales, these weren't consumables and likely survived, and if they didn't they don't have much value without the full cans...
Cheers,
Anthony