It's small, functional, requires no power, and will split one MIDI output into four

So as a note of caution, if all you have is an iPad and a simple one-out midi interface, this box might not work to provide multiple midi outs for you since the iPad will not provide enough power through the midi interface to power this thru box.

It does NOT work though with the mio USB/MIDI interface I just got because the interface doesn't supply enough power, so watch out for that when you drive it from a device.