Why use AN fittings?

I was at Summit Racing a few weeks ago trying to buy brake fittings (since they were the only place open at 8 PM), but they did not keep regular tube nuts in stock. All they had available were AN style fittings. What advantage do they offer over a regular fitting?

I was at Summit Racing a few weeks ago trying to buy brake fittings (since they were the only place open at 8 PM), but they did not keep regular tube nuts in stock. All they had available were AN style fittings. What advantage do they offer over a regular fitting?

I'm not sure what you mean by regular tube nuts, but i do know AN fittings are a 37degree flare fitting. Most AN fittings create a mechanical metal to metal seal, without the use of any gaskets. I use them all the time at work using pressurized gas, but haven't used them on my car. But then again, my car isn't really a performance car either.