Samsung I8552 Galaxy Win Dual Sim Unlocked Smartphone - 3G Network 900 / 2100 - Free Tmvel Dual USB Car Charger GSM 850 / 900 / 1800 / 1900 - GT-I8552 (SIM 1 & SIM 2) 3G Network HSDPA 900 / 2100 SIM Optional Dual SIM (Mini-SIM and Micro-SIM, dual stand-by) CPU Quad-core 1.2 GHz Cortex-A5 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.