iPad-3 is it Locked or Unlocked ?

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Are Tmobile or Sprint Lte bands compatible with Verizon or At&t?

List of LTE networks - Wikipedia, the free encyclopedia

Model A1459* (GSM)
LTE (Bands 4 and 17)

Model A1460* (CDMA)
LTE (Bands 1, 3, 5, 13, 25)

You shouldn't be concerned with which providers match bands. You should focus on which bands match the iPad specs.