An NPT-M x NPT-M male hex reducing nipple is used to connect two female NPT-threaded ports of different sizes, allowing a smooth reduction between pipe diameters within a system. It features male National Pipe Taper (NPT) threads on both ends and a hexagonal centre section for easy tightening with standard spanners or wrenches.
This type of fitting is commonly used in hydraulic, pneumatic, oil & gas, and industrial piping systems where a compact, pressure-tight transition between different thread sizes is required. The tapered NPT threads seal through thread interference, typically used in conjunction with PTFE tape or thread sealant.

