BLU ENERGY X Smartphone - With 4000 mAh Super Battery - GSM Unlocked - Grey Unlocked Dual Sim Smartphone, with Android 5.1 Lollipop 4,000 mAh Super Battery that lasts approximately 3 days with standard usage and over 30 days on standby with just one charge 5.0" HD display, 8MP Main Camera with LED Flash + 2MP Front Camera MediaTek Quad Core 1.3 GHz processor with ARM Mali-400 GPU, 8GB Internal Memory 1GB RAM Micro SD up to 64GB GSM Quad Band 4G HSPA+ (850/1700/1900/2100): US Compatibility Nationwide on all GSM Networks including AT&T, T-Mobile, Cricket, MetroPCS, Straight Talk and others. Please refer User Manual before use.