BLU Star 4.0 S410a Unlocked GSM Android 4.2 Smartphone with 4.0" Touchscreen - Yellow GSM 850 / 900 / 1800 / 1900, 3G / HSPA+: 850 / 1900 Android v4.2 (JellyBean) OS Digital QWERTY Keyboard 3.2 Megapixel Camera WiFi b/g Enabled, Bluetooth v3.0 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.