Apple iPhone 4S 64GB (White) - AT&T iPhone 4S Size 64 GB 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. 64 GB Storage Capacity (Estimated Free Space 56.4 GB)