Malleable Iron Pipe Fitting, 1/8 Inch 90 deg Elbow

These fittings are made from high tensile iron, so they should be able to handle outdoor use. But remember that they're black iron, and black iron can rust if it's exposed to moisture.

American Briggs Standard pipe threads are what this fitting uses. That standard is widely compatible with standard pipe thread fittings used across most industrial and hydraulic connections applications, so it should tie into your existing line without issue. Each opening is also chamfered, which makes getting it started on the threads a good bit easier during assembly.