Most of Verizon's high end phones recently (including the 8X) are LTE and Global which means they have the full array of radios: LTE, CDMA, and GSM. The GSM allows it to be used for roaming overseas where there is no CDMA. My last two phones (trophy and bb tour) while not 4G, were still global devices with sim cards but they were locked. I believe nowadays the GSM/HSPA radios are unlocked out of the box but the LTE isn't so they can be used on other networks, but only on 3G.