Motorola Defy Mini XT321 Unlocked Dual SIM GSM Phone with Android 2.3.6 OS, Touchscreen, Wi-Fi, GPS. 3G and Bluetooth - Black GSM 850 / 900 / 1800 / 1900 - SIM 1 & SIM 2 HSDPA 850 / 2100 - SIM 1 only Operating System - Android OS, v2.3.6 (Gingerbread) microSD, up to 32 GB Dust and water resistant Phone 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.