The Neutrik NL4MMX is a lockable 4-pole speakON barrel adapter. It joins two speakON female cable connectors (the NL2FX/NL4FX family and similar NL2/4F types) end to end, so two speaker cables can be linked into one longer run, or it can be locked permanently onto the end of a cable to turn a female-ended lead into a male-ended one. A second lock lets it be secured permanently to the cable connector, which is useful on touring and rental speaker looms where adapters otherwise go missing, and the printed 'use this side for secure connection' marking shows which end takes the permanent lock. All four poles are carried straight through, so it works with 2-pole and 4-pole speaker wiring. Neutrik rates the contacts at 15 A rms continuous (30 A for audio signals at 50 percent duty cycle), with silver-plated bronze contacts, a glass-reinforced polyamide shell and more than 5,000 mating cycles. It is for loudspeaker signals only: Neutrik warns that speakON must not be used for AC mains power.