BLU Studio 7.0 Unlocked 4G Phone, 1.3Ghz Dual Core, Android 4.4 KK, 4G HSPA+ with 5 MP Camera - Global GSM -(Grey) GSM Unlocked 4G Smartphone 8GB internal storage + 1GB RAM with Micro SD Slot up to 64GB MediaTek Dual Core 1.3 GHz Processor with Mail 400 GPU Android OS, v4.4 (Kit Kat) 5MP Autofocus Main Camera, 2MP Front Camera GSM Quad Band and 4G HSPA+ (850/2100MHz Bands): Works in all GSM Networks on Voice and 2G. For 4G HSPA+ Speeds, Compatible in the US on AT&T, Cricket, and Internationally when Roaming in Europe, Brazil, Asia, and other markets. Not compatible with T-Mobile, and MetroPCS. 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.