Complete foot valve assembly has female NPT threads to connect to a male NPT threaded connection for a tighter seal than straight threads.
It is made of carbon steel for hardness and strength with a rubber valve in the flapper assembly to keep water in the valve when the pump stops pumping (priming the pump) and a strainer to keep debris from entering the system.
It is painted to reduce corrosion. It must be installed in a vertical position. This foot valve is used to keep a pump primed in liquid flow applications.