A female inverted flare adaptor taking AN3 on one side and M10x1.25 on the other, with a 19mm hex. M10x1.25 inverted flare is one of the most common metric brake port threads, found across a huge range of Japanese and European master cylinders, calipers and proportioning valves, which makes this the adaptor most often needed when converting a car to braided AN3 brake lines. Inverted flare is a distinct seat style from concave seat, and the two are not interchangeable, so identify what your component actually uses before ordering. The 19mm hex is larger than the concave seat version in this range, giving good spanner purchase where the fitting sits deep against a caliper body or bracket.