iSIM is built into a dedicated Tamper Resistant Element (TRE) on the System on Chip (SoC) and provide all the same functionality as an embedded SIM (eSIM). Unlike MFF2 embedded SIMs, which must be soldered onto the circuit board, iSIMs are a dedicated chip component. The iSIM is incredibly small, measuring just 1mm by 1mm, much smaller than the MFF2 and standard SIM card form factors.