This is a factory issued Simple Mobile Micro SIM card, re-sized at the factory to fit the iPhone 4, 4S and other devices that require a micro SIM card. Phones must operate on the "1700" 3G frequency band to get 3G data transfer speeds (or 4G if phone is 4G capable). iPhones must be unlocked and jailbroken. After receiving your SIM card, just go to MySimpleMobile.com to activate it, then pop it in your phone* and start calling. You can choose an Unlimited Simple Mobile calling plan from of $40 or $50 per month.