No, we are a duo. I sing and play guitar, he does the keys along with the backing tracks.
We use them so we can quickly change our set.
www.karaoke-version.co.uk
and we put them on an ipad with Stage Trax. You can add lyrics, chords and time code it, so that the lyrics light up when you have to sing. (you have to set it up but once done, it's great)