Huawei Ascend Y520, 4GB, Dual Sim, Factory Unlocked (Black) GSM 850/900/1800 3G 850/1900/2100 Memory RAM : 512M eMMC ROM : 4GB MicroSD (up to 32GB) Operation System AndroidTM 4.4 CPU MTK6572 Dual-core 1.3GHz Display 4.5 inch LCD FWVGA (854 x 480) 256k colors Auto rotate (G-sensor) Camera 5.0 Mega pixel FF primary camera 0.3 Mega pixel front camera Video recording/video playback 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.