All Mintt phones use the nano-SIM card - the smallest size
The Mintt A3 and DUO3 have removable back covers. Just use your fingernail to prise off the back using the slot at the top right corner of the phone display. There are two SIM card slots and one micro SD card slot for memory expansion.
The Mintt S2, X3 and Y3 have a removable SIM tray. Use the supplied SIM tray tool to pop out the tray by inserting the tool in the small hole at the edge of the tray. You can either install 2 SIM cards or one SIM card and a micro SD card
You can transfer your existing SIM card into your new Mintt phone
It needs to be a nano SIM - the smallest kind - used by most phones these days. if yours is an older larger SIM then you will need a replacement from your Mobile Network - this is usually free.
Some SIM cards are multi size - and have cut-out surrounds that can be removed until you get to the correct size for your phone