7000 Series Ermeto Steel Flareless Fitting, 0.63 Inch Tube OD Small Hex Union

This fitting works with steel tubing, along with aluminum, hard or half copper, and stainless steel. It's also good for extra heavy wall tubing that you can't flare.

For most tube and fitting size combinations, the operating range on these runs from 1000 psi up to 4000 psi, so 3000 psi daily falls right in the middle of what this thing is built to handle. The Ermeto flareless design actually performs better under sustained high pressure than a lot of flared fittings do, partly because you're not relying on a flare seat that can fatigue or deform over time. Just make sure you're pairing it with extra heavy wall tubing, which is what this union is spec'd for.