A stub end is always used with a lap joint flange, as a backing flange. Stub ends are manufactured in all standard wall thicknesses, and available in sizes ranging from 1/2” to 48”. The dimensions for stub ends and related dimensional tolerances are defined in the ASME B16.9 standard. Light-weight corrosion resistant Stub Ends (fittings) are defined in MSS SP43. Stub ends are generally available in two lengths. MSS (Standard Length) and ANSI (Long Length).