Microsoft Lumia 435 8GB Unlocked GSM Windows 8 Smartphone - Black (International version, No Warranty) 2G: 850 / 900 / 1800 / 1900; 3G: 900 / 2100 Unlocked cell phones are compatible with GSM carriers like ATT 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. NOTE: Phone can be unlocked by making 5 mins call to activate the phone of outside USA. Microsoft Windows Phone 8.1, planned upgrade to Windows 10; Qualcomm MSM8210 Snapdragon 200 Chipset; Dual-core 1.2 GHz Cortex-A7 CPU Internal 8 GB, 1 GB RAM; Card slot microSD, up to 256 GB (dedicated slot) 2 MP Camera, f/2.7, 36mm w/ 480p@30fps Video