The AT&T, T-Mobile, and Verizon units, as well as the unlocked unit, do not work well on Sprint or on Canadian carriers. These units are model A1662. It has the LTE bands for AT&T (2/4/5/17/29), T-Mobile (2/4/12), and Verizon (4/13), but not all of Sprint's bands. Sprint's high-speed Band 41, also known as Spark, is missing. While you will get some Sprint LTE signal on bands 25 and 26, it won't be the best speeds.