BLU Studio X - US GSM - Unlocked Cell Phone (Black) 5.0" HD Display (720x1280): 8MP Main Camera + 2MP Front Camera Unlocked Dual Sim Phone, Android 4.4 KitKat upgradeable to Android 5.0 Lollipop MediaTek Quad Core 1.3GHz Processor with MALI 400 GPU, 8GB Internal Storage 1GB RAM with Micro SD Slot up to 64GB GSM Quad Band 4G HSPA+ (850/1700/1900): US Compatibility Nationwide on all GSM Networks including AT&T, T-Mobile, Cricket, MetroPCS, Straight Talk, Pure Talk USA and others