What is a SIM card?
SIM stands for Subscriber Identity Module. A SIM card is a small "smart card" for GSM/GPRS mobile phones that contains your personal account profile as well as saves important information (i.e. network information, account services, your mobile phone number, stored telephone numbers, SMS messages and more).
The SIM card must be inserted in the phone AFTER ACTIVATION in order for the phone to operate.
When in a new Red Pocket's Mango Plans package, it is about the size of a bank check card or a credit card.
Within, there is a small "punch-out" smart card which needs to be removed before inserting into the phone.