A metal nipolet is a type of pipe fitting used in piping systems. It’s essentially a combination of a nipple (a short piece of pipe with male threads on both ends) and a weldolet (a type of branch connection fitting). The nipolet allows for a branch connection to be made onto a pipe or vessel through welding, while also providing a threaded connection for further attachment of pipes, valves, or other fittings. This design offers versatility and ease of installation in various piping configurations.