HTC One Max Silver Unlocked GSM Android Phone 4G LTE LTE 800 / 900 / 1800 / 2600 32GB, 2GB RAM + microSD Slot Expansion up to 64GB Android OS, v4.3 (Jelly Bean) Qualcomm Snapdragon 600 Processor; Quad-core 1.7 GHz Krait 300 5.9" Super LCD3 Multi-Touchscreen w/ Fingerprint Sensor, Corning Gorilla Glass 3 and HTC Sense 5.5 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.