A 20-metre Speakon speaker cable with locking NL4 connectors on both ends, made to carry the amplified signal from a power amp to a passive PA speaker. It is tested before every rental, so it just works on the day.
This is a speaker-level cable, not a line-level or microphone cable.
It has a Speakon NL4 male connector on each end and runs 20 metres between the speaker output of a power amplifier and the input of a passive PA speaker or subwoofer.
In a live sound rig the mixer feeds the power amp, and this cable is the heavy feed that takes the amp's high-current output to the speaker cabinet.
That is the one job it does, and it is the pro standard for that job because the Speakon connector twist-locks into the socket and will not pull out under stage movement or cable tension.
Being honest about what it is matters, because Speakon looks similar to other stage cables. This cable carries amplifier output to passive speakers only.
It is not a microphone or line cable, and it does not plug into the line inputs on a mixer or the input of a self-powered active speaker.
Line and mic cables carry a tiny signal on shielded conductors, while a speaker cable carries a much stronger amplified signal on heavier conductors, so the two are not interchangeable.
Use this cable only between an amp and a passive speaker that both have Speakon NL4 sockets.
If your gear uses jack or binding-post speaker inputs, or you need to run a mic or line signal, choose the matching cable instead.