Unions

A Union is used to join two pipes without turning either pipe.

Pipe Unions are made in three parts: a female end, a male end, and a nut. The nut provides the necessary pressure to seal the joint when the male and female ends are brought together. Unions allow dismantling a fitting without disturbing the pipe.
Sizes are Nominal Pipe Size (NPS) - size chart

Pipe Fittings Unions