This AN4 90° adapter has a male flare on one end and a rotating female swivel on the other, so the hose can be aimed exactly where it needs to go after the fitting is torqued home. AN4 covers turbo oil feeds, brake and clutch lines, boost and vacuum reference plumbing and gauge senders, all of which tend to live in cramped, hot corners of the engine bay. Being able to clock the swivel means the hose leaves the port cleanly instead of being wound into position. Keep the 37° seats clean and avoid over-tightening — the cone seals well before the fitting needs to be forced.