SIM

SIM stands for Subscriber Identity Module. The tiny SIM card is mandated on GSM and LTE networks and identifies you to the network.

A SIM card is what holds your cellular plan and number. Swapping your SIM into a new phone or device moves your service and phone number to that new device.

SIMs come in a range of sizes – Full-Size is extinct, but Mini-SIM, Micro-SIM, and Nano-SIM are all in common circulation.

There are also eSIMs which are built into the device itself are not removable.