What is the most commonly used holding device by plumbers?

The pipe vise is a critical tool used extensively by plumbers to secure pipes during cutting, threading, or other installation tasks. Its design enables it to firmly grip various sizes of pipes, providing stability and allowing for precise work while ensuring safety. The ability to adjust the jaw size makes it versatile for different applications, accommodating both rigid and flexible materials used in plumbing systems.

In contrast, while the other tools listed serve important functions, they are not primarily designed for holding pipes in the same reliable manner. A pipe clamp, for instance, is typically used to hold pipes in place temporarily rather than providing the secure grip necessary for more extensive plumbing tasks. An adjustable wrench and channel lock pliers are functional for gripping nuts, bolts, or fittings, but they do not offer the same level of support and stability for pipe work as a pipe vise does. This makes the pipe vise the most commonly used holding device among professional plumbers.