Weldolets (also known as olets) are fittings that provide an outlet from a larger pipe to a smaller pipe (or one of the same size). The main pipe to which the branch connection is welded is commonly referred to as the run pipe. The pipe to which the branch is connected is called the outlet pipe. Olets come in all sizes, types, bores, and ratings, in a wide range of stainless steel, chrome-moly, and other alloy materials.