The ATOM X Cast is a live switcher unit which you can combine with the Atomos Ninja V. However, I would advise you to check out the ATEM Switcher Lineup, because those are much more powerful when it comes the their capabilities and you can also combine them with inexpensive monitors to also be able to see what you record / live switch.

The ATOMX Cast is nice, but at this point in time, I'd rather go with the ATEM Mini + Monitor than this combo (Especially the ATOM Mini Pro ISO is interesting because there you get a recording of every single camera and the program output instead of just having the program output which the ATOM X Cast will give you).