Voodoo Lab

I already have a x4 and just ordered an ISO-5. What is in the x4 expander kit that's not in the x4? Do I need a particular cable to run from the ISO-5 12 volt out to the x4 DC input?

I have two Pedal Power x4 units. I would like to have only one plug for both. Is there an adapter that would allow be to plug in both units so I only have one cable running to the power?

Thanks,
Chris