MST (Magnetic Secure Transmission) is the most commonly used near-field technology. It requires your card to be close to the terminal, typically between half an inch and two inches. This may pose problems depending on where you are trying to make your transaction. On the other hand, NFC (Near Field Communication) does not require you to have your card very close to the terminal. You can hold it about three inches away, providing a lot more leeway for making payments on the go.