 Connectors are assigned a gender, abbreviated M or F. An example of this is a "-inch female adapter NPT", which would have a corresponding male connection of the same size and thread standard (in this case also NPT).This section discusses fittings primarily used in pressurized piping systems, though there is some overlap with fittings for low-pressure or non-pressurized systems.Specialized fittings for the latter setups are discussed in the next major subsection.