4 pole chassis connector, black D-size flange, self tapping screw holes (A-screw), switchable version of NL4MD-V with 8 vertical PCB contacts (4 switching contacts). Switch is closed unless mating of speakON cable connector. This chassis connector is not airtight. The speakON panel mount connectors are the standard chassis connectors for loudspeaker / amplifier interconnections. They feature a unique metal locking system, making contact only once fully locked. The speakON receptacles are robust, versatile and easy to terminate.