Connector with a BSP male thread on both ends. It joins two female threads, for example a pump port and a female adapter, with threads of the same size or of different sizes.
Equal threads from 1/8" to 2" and many reducing combinations (for example 3/8" - 1/4" or 1" - 3/4")
BSP is the 55° parallel pipe thread (ISO 228-1); a 1/2" BSP male thread measures about 20.9 mm across the outside
The option shows both threads. Check the thread size and how the port seals (washer, O-ring or cone) before ordering.