eSIM stands for embedded SIM. eSIM capabilities are available for all form factors: 2FF (Mini), 3FF (Micro), 4FF (Nano), and MFF2 (the soldered sim chip). The main difference with a standard simcard is the ability to provision the simcard remotely. This means that different carrier profiles can be stored on the sim and subsequently downloaded over the air. It allows a customer to switch between the two without changing the physical simcard itself.