Thing is mixture, they all still work as on dongle principal (mobile wifi) I use Three (wifi) it's powered from the internal battery, no leads required. It still does the same internet connections as a dongle. The only difference being a dongle needs power from the lappy.
Please dear, do me a favour and
READ !
The operating principle may be the same, BUT UNLIKE DONGLES, MIFI UNITS DO NOT NEED STUPID DRIVERS ... standard Wifi will do !