Apart from the USB cable, it doesn't require anything else to function.
Today everybody keeps talking about size. Size matters, size doesn't matter... Phones that already went from big to relatively small are coming back looking bigger than ever. With notebooks, advancing meant going from bulky to thin and almost feather-light. Because with them in mind, the most important factor is portability. Using laptops regularly we often miss having a larger, comfier working space. Another monitor would do the trick, but I can't take it with me to a local bar, where I might do some work. Hence, a portable monitor would be good. But not the one you need to plug into a wall socket. I am talking about USB monitors, which are easy to carry around and all you need to do to get them working is plug them into your computer's USB port.
If you do a little search, you can find several monitors of this kind. For example, AOC has them. And a couple of days ago they presented the new 16-inch 1080p USB 3.0 version (E1659FWUX-PRO), which also features a built-in DisplayLink USB graphics technology, so you can use it as a part of a multi-monitor display setup.
Users can choose to work in portrait or landscape mode, without having to mess with the settings: you just flip the monitor to the side and the displayed content rotates automatically. By the way: AOC's monitor come with a folding stand, so you do not need to get any duck tape or other DIY accessories to make the monitor stand in place.
It's Mac and PC compatible. Price: acceptable 199 dollars.