The AN12 180-degree PTFE hose end reverses the biggest lines in a system entirely within the fitting. On suction, scavenge and large cooler circuits the hose has no usable tight bend radius at all, so the fitting has to provide the turn or the routing has to change. It seals on an olive compressed onto the PTFE liner as the socket nut pulls the nipple in, and can be stripped and rebuilt like the rest of the range. Expect to need good access and a large AN spanner, clamp the hose so its weight is carried by the chassis, and pressure test before use.