This AN4 hose end puts a 120-degree bend into the fitting body, effectively doubling the hose back on itself. That is the answer when a straight or 90-degree end would foul a cam cover, turbo housing or chassis rail and you need the hose to leave the port and immediately head back the way it came. The AN4 swivel nut lets you align the joint without winding tension into the hose, which is important with a bend this severe. It is a reusable socket-and-nipple design suited to braided hose. Angled ends are less common than straight, so plan routing before committing to hose lengths.