Leaderboard

Not sure where you are with the fitting. I haven't checked broadly on this, but they seem to be a standard item carried by hardware outlets. That version's usually plastic, and might cost a couple of bucks. It looks like this (ones I have seen have also been grey or greenish-blue). https://www.shopnebulizer.com/p-salter-labs-nipple-nut-plastic-hose-barb-fitting.html?gclid=Cj0KCQiAs5eCBhCBARIsAEhk4r7tJ_qJlVbD-LYAVblIQDDS1UQmdfwxpfpdHXiWOyF99pUai8qpIFQaAuFpEALw_wcB If I was going in to ask, I think I'd ask for a barb fitting for an oxygen regulator. Or, a thingie you attach to an oxygen regulator so you can attach a tube to it. You could bring your reg and a piece of the hose tube to test it.