The VS−4X is a high−performance switcher for balanced stereo audio signals on XLR connectors. It switches any one of four stereo signals to a single stereo output.

From my experience you can not select but one input at a time. The product is outstanding, though. I am in to very high end audio and have high end audio components connected like Mark Levinson, Theta, Magnum Dynalab and notice no signal degrade.

YES, kramer sell a rack solution for this model, be aware that this solution is hard to find, i tried and never found a seller whit the product in stock.

Thanks to everyone for their feedback.