A SIM card comes in 3 different sizes and it makes it possible for your device to connect with our carrier’s network towers. SIM cards are transferable from device to device (if the device is unlocked), and you can transfer your phone number to any SIM card.
So you can insert a new SIM card into an older flip phone and it should work great. Many international travelers buy SIM cards locally to use in their phones to lower long distance costs.“GSM” stands for Global System for Mobile Communications.
The GSM LTE Network tends to have the highest number of compatible devices of all major networks. As a result the GSM SIM card is the most common type of SIM card.
To install a SIM card, you will need to find the SIM card slot in your device. Sometimes you will find the slot on the outside of your device, typically on the side (like an iPhone). Some other devices may have the SIM card slot hidden under a cover, next to your internal battery. A quick Google search may help you locate your SIM card slot.