A larger two-step reduction, with an AN10 female 37° flare seat on one side and an AN6 male flare on the other. It suits situations where a big component port — a swirl pot, cooler, tank fitting or pump housing — is AN10 but the line running to it only needs to be AN6, such as a return, vent or secondary feed. Doing the step in one fitting is tidier and shorter than chaining a 10-to-8 and an 8-to-6 together. Because the drop in bore is significant, avoid using it on a suction or main feed line where the AN10 size was specified for a reason.