Which fitting is used to connect two pipes of different diameters?

The fitting used to connect two pipes of different diameters is known as a reducer fitting. This fitting is specifically designed to transition between pipes of varying sizes, allowing for a smooth and secure connection. When plumbing systems require different sized pipes, reducer fittings are essential for maintaining proper flow and pressure, preventing issues such as leaks or blockages that may occur with mismatched pipes.

In this context, the reducer fitting can either reduce the diameter from a larger pipe to a smaller pipe or vice versa. This capability is crucial in ensuring that plumbing systems function efficiently, as it allows for optimal adaptability in various plumbing applications, including water supply lines, drainage systems, and HVAC installations.