In the market so many tools are available to unlock the 3G/4G USB stick.you can unloack any of the USB modem by DC-Unlocker.there are some free tools also available but the DC-unlocker is very populer currently.
Following Modem you can unlock
- ZTE
- ZTE phones
- Huawei
- Maxom
- Micromax
- Skypephone
- Toshiba