Micro Data SIM (3FF) is a smaller version of Mini Data SIM (regular-sized SIM, also called 2FF). Micro Data SIMs come with mobile plans which are used purely for Data usage, and available in Postpaid, Pay As You Go® and Enterprise plans. Currently, there are relatively few devices which use Micro SIMs instead of the regular sized SIMs. An example of one such device is the Apple iPad.