A Stub End always will be used with a lap joint flange, as a backing flange; both are shown on the image below. This flange connections are applied, in low-pressure and non critical applications, and is a cheap method of flanging. In a stainless steel pipe system, for example, a carbon steel flange can be applied, because they are not come in contact with the product in the pipe.

Stainless Steel Stub End with Lap Joint Flange

Stub Ends are available in almost all pipe diameters. Dimensions and dimensional tolerances are defined in the ASME B16.9 standard. Light-weight corrosion resistant Stub Ends (fittings) are defined in MSS SP43.