It's basically an extremely small(credit card sized) computer/motherboard. It comes equipped with all the necessary ports such as HDMI, USB, SD Card reader(for the hard drive and Linux OS), meaning that this tiny device. An be taken and moved around with absolute ease, and connected into a set up in much the same way as a full sized desktop.
And a massive bonus of this, is the price! It currently ranges at around $25-$35, making it super affordable! I've been looking for an excuse to really get back into Linux like I used to be, I think I've found that excuse.