If you have full specs for one you are looking at, we can give a better idea of compatibility!
Does T-Mobile support unlocked Netgear AC815S hotspot with the following bands?
4G LTE Bands : 2, 4, 5, 12, 17, 29 and 30
4GHSPA+ with enhanced backhaul
3G–UMTS : 850/900/1900/2100MHz
GSM/GPRS/EDGE : 850/900/1800/1900MHz
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