It's 10 gauge wire. Banana plugs on the speaker end are fused onto the wire, so I don't particularly (well, at all) want to start tearing it up in order to tie them together. My thinking is that on a 15 ft run a single 10 gauge is more than enough and putting both together wouldn't yield much of an upside. On the other hand, since I already do have the cable, I'd like to try it. The easiest thing I was hoping for is some sort of a banana plug adapter (two in, one out) that I'd be able to use, but a cursory search of the Internet so far revealed nothing.