Samsung Galaxy S4 I337 16GB 4G LTE AT&T Unlocked GSM Smartphone - Blue GSM 850 / 900 / 1800 / 1900, 3G: HSDPA 850 / 900 / 1900 / 2100, 4G: LTE 700 MHz Class 17 / 1700 / 2100 5" Super AMOLED Capacitive Multi-Touchscreen w/ Protective Corning Gorilla Glass 3 Android v4.2.2 (Jelly Bean), upgradable to v4.4.2 (KitKat), Quad-Core 1.9 GHz Krait 300 Processor, Chipset: Qualcomm APQ864T Snapdragon 6, Adreno 320 Graphics 13 Megapixel Camera (4128 x 3096 pixels) ) w/ Autofocus, LED Flash + Front-Facing 2 Megapixel Camera, 1080p@30fps, dual video call + Video 1080p@30fps, dual-video rec., Internal Memory: 16GB storage, 2GB RAM + microSD Slot Expandable up to 64GB Unlocked cell phones are compatible with GSM carriers like AT&T and T-Mobile as well as with GSM SIM cards (e.g. H20, Straight Talk, and select prepaid carriers). Unlocked cell phones will not work with CDMA Carriers like Sprint, Verizon, Boost or Virgin.