A stainless inverted seat adapter linking an AN3 line to a 7/16-20 imperial thread. This size shows up on brake master cylinders, unions and proportioning valves, typically on lines a step larger than the common 3/8-24 ports. The inverted seat gives the factory pipe flare a proper female cone to bed against, which a plain AN male flare cannot do — get this wrong and the joint weeps no matter how hard it is tightened. With the AN3 connection on the other end, it lets braided AN3 hose serve an imperial system with the original pipework left intact. Take care distinguishing 7/16-20 from 7/16-24; the diameters match and only the pitch differs. Bleed the circuit fully once fitted and check for weeping under firm, held pedal pressure before driving.