Neutrik NL4MPR panel mount Speakon connector
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The Neutrik NL4MPR is a large round panel mount to replace older EP4 sized holes
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 male. Go figure....