Sonim XP5 4G LTE The Worlds Most Indestructible Cell Phone AT&T DOES THIS DEVICE NEED A SIM CARD: Yes it does Being that this device is Purchased outright it will work on any AT&T active micro size SIM Card The sim card does not come included and you will need to contact AT&T to acquire your complimentary Sim card (Free from AT&T with activating of an account) Locked to the AT&T for at least the first 6 months contact AT&T for assistance with Unlocking this Device WHAT NETWORK FREQUENCIES ARE SUPPORTED BY THIS DEVICE: 4G-LTE Bands 2, 4, 5, 7, and 17 4G HSPA+ with enhanced backhaul 3G - UMTS 850/1900/2100MHz GSM/GPRS/EDGE 850/900/1800/1900MHz WHAT CAN YOU TELL ME ABOUT THE BATTERY: Well the capacity has 3180mAh Li-Ion which in actuality can get you Talking for 25h and can stay on Standby for 25 days now that a really long time WHY IS THIS THE WORLD RECORD HOLDER FOR THE MOST INDESTRUCTIBLY CELLPHONE: Well one may call this a Brick and they won't be wrong as it is Quite Bulky though with an On-demand push to talk and applications geared for the Heavy-Duty User this phone won't let you down as it is after all indestructible when screwing on the back door and sure not to insert too much pressure as this can strip the screws rendering a device no longer waterproof