Review on 10pcs Lollipop Speaker Wire Cable to Audio Male RCA Connector Adapter Jack Plug Set - Enhance Sound Quality! by Katie Washington

I used them with 14 gauge wire (because I had it on hand). I don't think you could reasonably use anything more with them, but they work pretty OK well. 16 gauge wire is probably what you "should" use and will work for most speaker setups. If you already have a cable and just want to connect speakers (or other RCA component) without having to buy pre-made cables, these are fine. As at least one reviewer has mentioned, don't twist the wires together. If you're using heavier gauge wire, it's easier to insert it carefully and not twisted with a 16 gauge or higher, although it shouldn't matter.