Huawei has recently launched E8372h and E8372s 4G LTE wingle. If your E8372 is locked to a particular network and you can not use any another network provider SIM then you must want to unlock it. Unlocking is simple and one-time work.
If your device is Huawei E8372s, then just change the default SIM with another carrier SIM card and plug it to PC. It will automatically redirect you to the unlocking page and will ask you for SIMLock / unlock code. Just enter correct NCK / unlock code in the box and click on OK, the device will be unlocked permanently.
Additionally, you might be interested in dashboard / WebUI and Firmware update also:
Firmware / WebUI / Dashboard changing is risky and may it dead your device. While updating the firmware, it may ask you password, generate the firmware code from universal master code tool.
Note: Don’t try to use the unlock code which is generated by universal master code software. It generates old algorithm code and does not work with Huawei E8372h and E8372s devices.