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AN Fittings Explained!

You may have heard of an AN fitting, but do you know what it is? 

AN fittings (aka Army Navy) were originally designed for use in Aerospace and the Military.

Today, they are known in the high performance world as the most common way to plumb fluids. Literally any fluid in a car can be plumbed using AN hose. 

For many years, AN fittings were only available in a blue/red combo of fittings, with stainless braided hose. Now days, there are many different colors of hose AND fittings to further customize a build!

The most common ones we offer at Pro Touring Store are black anodized fittings, and black nylon braided hose. We also have PTFE lined conductive-core hose for fuel or very high pressure applications, that comes in either stainless braided, or with a black covering.

There are a bunch of fitting manufacturers today. I can name over 20 easily. We have tested numerous fittings in numerous applications, and we only sell from manufacturers we believe in.

 **Pro tip: If you're ever in a bind and need an AN hose or fitting quick, they're the same thread/flare as a fitting called JIC - available at most any hydraulic hose supplier. 

AN Flare

AN fittings seal on a tapered seat, which is machined at 37 degrees. Standard flares (brake fittings etc) that you may be used to, are a 45 degree flare and not compatible with AN.

Since AN fittings seal on a tapered surface, there is no need for any type of sealer. It’s best to leave everything dry, with the exception of a small amount of anti-seize on the AN threads to prevent galling. 

Here is a great guide that was taken from Summit Racing’s website that explains the nominal tube size and the thread size of common AN fitting sizes.

**Note: -2 and -5 are not valid aftermarket sizes. Also anything over -20 is not common. 

 Hose Ends

Hose ends are the part that installs onto AN hose. Most hose ends have a female AN connection. Each manufacturer has their own tolerances, and it’s best to stay with one hose/hose end manufacturer. Do NOT mix and match brands! (Trust us, we’ve been there).


AN O-Ring aka ORB

ORB or O-Ring Boss fittings utilize the same thread as AN, but the type of seal is an O-ring instead of a tapered surface. ORB fittings are commonly found on aftermarket fuel systems: Fuel rails, regulators, and pump hats, for example.

AN Adapters

Want to run AN but need to adapt to another thread? There are adapters for nearly any application. If you don’t see it on our site or need help finding something, contact us today!