Which feature is characteristic of AN flare fittings?

• A. An identifying shoulder between the end of the threads and the flare core
• B. A threadless design with no shoulder
• C. A groove around the flare
• D. A color-coded ring at the base of the flare

Answer: (A)

The feature being tested is the identifying shoulder on AN flare fittings. This shoulder sits between the end of the threaded part and the flare portion, giving a precise reference point for where the flare begins. It serves two key purposes: it identifies the fitting as an AN flare and provides a seating datum so the flare seats correctly when the nut is tightened. As the nut compresses the flare onto the conical seating surface, a tight metal-to-metal seal is formed. The shoulder also prevents the flare from being driven too far in or bottoming out, which helps ensure a reliable seal.

The other options don’t fit because AN flare fittings are not threadless, they don’t depend on a groove around the flare, and they aren’t identified by a color-coded ring at the base of the flare.