Neutrik NLJ2MDXX-V

These work great and are (almost) a drop-in replacement for a normal speakon connector. Note that they protrude outwards a few extra mm to allow for the length of a jack connector.

I've been putting these in every speaker I build/work on, because it means that if I forget a speaker cable at a gig, I am much more likely to be able to get a spare jack-jack cable to replace it in an emergency than a speakon cable (or speakon to jack like many mini heads require).

10/10 would recommend.