What is a key characteristic of a shoulder nipple?

A shoulder nipple is characterized by having threaded ends with an unthreaded section (or pipe) in between. This design is essential for connecting two threaded fittings while providing a smooth transition for fluid flow through the unthreaded middle section. This is particularly useful in plumbing and piping applications where a seamless connection is required to prevent turbulence or blockage as fluids pass through.

The threaded ends of a shoulder nipple allow it to securely attach to other fittings, while the unthreaded section ensures that the internal diameter remains consistent, minimizing friction and facilitating better flow. This makes it a versatile component in various applications but does not inherently limit its usage to specific pressure conditions or allow for quick disconnects like other types of fittings designed for that purpose.