A stub end and its associated slip-on flange allows quick disconnection of the particular section involved as well as easy alignment of mating flanges. Stub ends are installed in pairs and mated together with two slip-on flanges. The surface of the stub end has a phonographic serrated gasket surface which prevents leakage at the joint.
There are two basic types of stub end, ANSI types A & B long barrel, and M.S.S. types short barrel. Under certain design criteria such as temperature or pressure, it is not acceptable to have the joint between stub end and pipe in close proximity with the flange joint, in these applications ANSI types are used.

Type A stub ends are used with lap joint flanges.

Type B stub ends are used with slip-on flanges.