Oh boy... PreSonus Capture (the new name, used to be Duo) is iPad only, they don't make an iPhone version, probably due to the screen size constraint. However, maybe that isn't needed. You plug your iPhone into the iTwo with a regular iPhone cable, and then you will need a standard USB printer cable and a power block to power the iTwo. Many power strips have USB power ports now, that should be enough power. Once you do that, plug in your mic into one of the XLR jacks on the iTwo, and try a test stream to see your streaming app on your iPhone picks it up.