For reducing the thread
The Brass Threaded Nipple, reduced has both a male thread and a female thread. It is used to reduce the thread, e.g. with pumps.
With 33.3 mm (G 1") male thread and 26.5 mm (G 3/4") female thread.
With 33.3 mm (G 1") male thread and 26.5 mm (G 3/4") female thread.