The idea of a "mobile device" is a little tough to get a gauge on. For the purposes of Phone Arena, we tend to limit the idea to smartphones, tablets, wearables, and occasionally cars, but usually just the first three categories. There is always a blurry line because for a long time, "mobile" essentially meant "a device that fits in your pocket", like a phone or PDA. Then, the definition was expanded to include tablets, but the reasoning there was tenuous at best. Tablets were packed into the "mobile" idea mostly because they ran traditionally "mobile" operating systems like iOS and Android and because they had similar input methods (touchscreens).