As depicted in the figure above, a traditional Male connector (Standard Polarity) consists of an outer body, a ferrule and a center pin. The threaded portion is inside the connector.

On the other hand, a traditional female connector (Standard Polarity) consists of an outer body, a ferrule and a receptacle instead of a center pin. The threaded portion is outside the connector.

In Reverse Polarity Male and Female connectors the 'center pin' of the Male connector is swapped with the 'receptacle' of the Female connector i.e., a reverse polarity male connector has a receptacle at the interface instead of a center pin and reverse polarity female connector has a center pin at the interface.

The basic idea behind using reverse polarity connectors is to prevent a user from trying to connect the wrong type of connector i.e a male connector to a male connector or female connector to a female connector as this can damage the connector and result in signal degradation at the connector interface.