If you want to run a -4 AN line for your stand alone hydro brake install, this fitting will do the job. It's a steel fitting made to work with the outlet port common to Willwood master cylinders and connect a -4 AN line.
We also have dual fitting kits for inline style masters with two ports. UH-DB-LK-S4
1 - 3/8" banjo to -4 AN fitting.
2 - 3/8" copper washers
Hydro, master and lines not included.