New ASUS Zenfone 5 16GB 4G LTE (Unlocked) A500KL 5" Micro Sim 2GB RAM Black 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.