A fitting is a component of a pipeline that connects sections of pipes. Primarily, fittings are used to create branches, transitions between different diametersâeither increasing or decreasingâ, for making turns at various angles, as well as for the straight-line connection of individual pipes. No matter how many types of pipes are produced today, regardless of the material from which they are made, the same number of fittings is produced for each type of pipe in terms of usage.