Union Hard Line Fitting,
available in : 5/16, 3/8, 1/2
This fitting does not require you to flare your hard line you simply slip on the Tube Nut then fit the Compression Olive and followed by the Tube Adapter simply tighten the Tube Nut while holding Tube Adapter. The olive will compress on to the pipe creating a seal which has been tested on stainless steel pipe up to 300psi.