This QNH-530 dual mode SIM card walkie-talkie, which is also called PoC walkie-talkie, is one of our top-selling 4G walkie-talkie, its operation systme is Linux, it has GPS function, the good point is that it has LTE/4G + VHF/UHF analog version, which means that as long as you have this Q12 walkie talkie, you can not only talk to analog walkie-talkies, but also SIM card walkie-talkies.