7000 Series Ermeto Steel Flareless Fitting, 0.19 Inch Tube OD Small Hex Union

It's designed to handle stainless steel tubing, along with aluminum, hard or half copper, steel, and extra-heavy wall tubing. The key is that it works with tubing that can't be flared.

No flaring needed at all, which is one of the main reasons folks reach for this fitting. It works with aluminum, hard or half copper, steel, stainless steel, and extra heavy wall tubing that can't be flared. That last category is worth noting since extra heavy wall tubing often can't be flared without cracking, so a flareless design like this one is pretty much the only practical option for those situations.