Neutrik NL4FX in-line Speakon connector

Neutrik NL4FX is a 4 pole female NL4 Speakon connector used on speaker cables.

The Neutrik Speakon connector is the industry standard for loudspeaker connections.  The Speakon connector is also commonly known as an NL4 (4 pin) as this is the most commonly used Speakon.  The are also availble in 2 pin (NL2) and 8 pin (NL8).  

The differences between the NL2 and NL4 are subtle and worth noting.  An NL4 cable connector will NOT mate with a NL2 chassis connector, however an NL2 cable will mate with an NL4 chassis mount.  This is not normally a problem as most amp and speaker manufacturers use NL4 on the units, but some cheaper brands use the NL2 to cut costs.

The Male and Female types are also reversed from what you would think.  This is actually the female.  Go figure....