NEW Unlocked Huawei E3276 LTE 4G 3G modem USB stick (E392 E398 K5005 K5007) 2G GSM 850/900/1800/1900 MHz 3G UMTS 2100MHz ; TD-SCDMA 1900/2100MHz 4G LTE FDD 2600MHz ; TDD 1900/2300/2600MHz It is unlocked for GSM use.CDMA sim cards will not work with this unit as described in the listing.The cover is hard to open and is designed that way to protect the sim slot. Software updates can be performed by attaching the usb to your computer and auto updating. Technology is always updating their OS.