Verizon, AT&T, T-Mobile, and Sprint are the for major cellular service providers in United States. If device is an unlocked device: for CDMA (Verizon/Sprint) select Verizon and for GSM (AT&T/T-Mobile) select AT&T. If customers understand coverage area and would like T-Mobile, select T-Mobile. (PLEASE BE SURE DEVICE IS UNLOCKED AND COMPATIBLE!)