What Is a Plumbing Ferrule?

A plumbing ferrule is a cylindrical-shaped fitting used to connect two pipes of different sizes. It fits over the smaller-diameter pipe and has screw threads on the inside for attaching to the threads on the larger pipe. Ferrule usually refers to a plumbing union, which is one of the most popular plumbing fittings. It allows quick and easy adjustment with its three parts-the nut, ferrule, and body with threads.

Ferrule can also refer to a thin sheet of metal that protects the end of a pipe or a plumbing system. It is mostly known as a pipe sleeve.