BLU Energy Diamond -With 4,000mAh Battery- US GSM Unlocked -Grey Unlocked Dual SIM smartphone, Android 6.0 Marshmallow 4,000 mAh massive battery, OTG capability allows you to charge other Electric devices 5.0 IPS technology display; 5MP Autofocus Main Camera + 2MP Front Camera with flash MediaTek 6580 1.3 Quad Core Processor with Mali-400 GPU, 8GB Internal memory 1GB RAM Micro SD up to 64GB GSM Quad band 3G HSPA+ (850/1700/1900): US compatibility Nationwide on all GSM Networks including AT&T, T-Mobile, Cricket, Straight Talk, Pure Talk USA, and others