Samsung Galaxy Grand Prime GSM Unlocked Cellphone - Gray DOES THIS DEVICE NEED A SIM CARD: Yes it does Being that this device is GSM unlocked it will work on any GSM Network with a Micro size SIM card The sim card does not come included (Free from most carriers with activation of an account) WHAT NETWORK FREQUENCIES ARE SUPPORTED BY THIS DEVICE: This device will support bands 850, 900, 1800, 1900 MHz NOW REALLY WHERE CAN I USE THIS DEVICE: Internationally Compatible in 100 Countries that support GSM Frequencies (contact your network provider prior to purchasing for verification that they support GSM frequencies). WHAT DOES UNLOCKED REALLY MEAN: Unlocked devices are compatible with GSM carriers as AT&T and T-Mobile as well as with GSM SIM cards (Ask your network for verification)Unlocked Devices will not work with CDMA Carriers like Sprint, Verizon, Boost or Virgin HOW LONG CAN I EXPECT THE BATTERY TO LAST ME: Up to 17 hours of talk time.