An inverted seat adapter that pairs an AN6 37-degree flare with an 11/16 x 18 inverted flare thread. Inverted flare is the sealing system used on original-equipment steel hard lines for brakes, fuel and clutch circuits, and its seat geometry is not the same as an AN flare, which is why an adapter of this type is required rather than simply forcing one onto the other. The 11/16 x 18 size is one of the larger inverted flare threads and typically appears on bigger fuel or hydraulic lines. Use it to bring factory hard-line plumbing into a -6 AN braided system without cutting or reflaring the original tube.