technology
eSIM
A SIM card built into the phone and provisioned digitally — convenient for travel, but rare on dumbphones, which favor physical SIMs.
An eSIM is a SIM chip soldered into the phone and provisioned with a QR code instead of a plastic card. Smartphones have embraced it; dumbphones largely have not — nearly every current feature phone uses a physical nano-SIM.
That is worth knowing for two reasons. First, moving your number to a dumbphone usually means requesting a physical SIM from a carrier that may default to eSIM. Second, the physical SIM has a quiet benefit for intentional users: swapping your number between a weekday dumbphone and a drawer smartphone takes ten seconds and no app.