A stainless inverted seat adapter taking an AN3 line to a 3/8-24 thread — the imperial size widely used on American brake plumbing for 3/16″ pipe. The inverted seat is the key feature: factory brake pipes are flared to seat against a female cone, which an ordinary AN male flare will not seal against, so this adapter provides the correct seat on the 3/8-24 side while presenting an AN3 connection on the other. It is the sensible way to fit braided AN3 hose to an imperial-threaded master cylinder, union or calliper without re-flaring the existing pipework. Note that 3/8-24 and 7/16-24 share a pitch and are easily confused, so check the thread diameter before ordering. Bleed thoroughly after fitting and inspect the joint under sustained pedal pressure.