Samsung Galaxy S4 I337 16GB 4G LTE Unlocked GSM Smartphone - Black (Certified Refurbished) Unlocked cell phones are compatible with GSM carriers like ATT 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. DISPLAY: Super AMOLED capacitive touchscreen, 16M colors.1080 x 1920 pixels, 5.0 inches (~441 ppi pixel density).Corning Gorilla Glass ,3TouchWiz UI. 16 GB Storage Capacity (Estimated Free Space 8.56 GB)