A straight female flare swivel adapter in AN12, our larger-bore option in this family. At AN12 the hose is stiff and heavy, which makes it very difficult to twist a run into alignment during assembly. The swivel joint solves that: it decouples the sealing face from the orientation of the hose, so the flare can be torqued correctly while the line sits along its natural path with no wind-up loaded into it. That matters because a twisted large-bore hose puts constant load on every fitting in the circuit. Typical uses are high-flow fuel systems, dry sump scavenge lines and big oil cooler runs. Confirm both mating parts use the 37-degree AN flare seat.