Samsung Galaxy Exhibit SGH-T599 Gray (GSM Unlocked) Android Smartphone (Certified Refurbished) This Certified Refurbished product is tested and certified to look and work like new, with limited to no wear. The refurbishing process includes functionality testing, inspection, and repackaging. headphone and SIM card sold separately 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. THIS 4G Samsung Galaxy Exhibit SGH-T599 IS (FACTORY UNLOCKED) Works with t-mobile network or any gsm network Gsm internationally or in the USA networks like Simple Mobile, net10 H2o, Like a Mobile AT&T and OTHER GSM SERVICE WORLDWIDE Make sure to input your carrier's APN settings for the phone to work properly. This phone will NOT work for Verizon or Sprint accounts. It will work for GSM service like AT&T or T-Mobile.