goTenna is the best solution for emergency situations. It enables you to use your iOS or Android devices to send SMS or forward your GPS location even when you’re out of cell coverage area or when Wi-Fi is not available. It pairs with a smartphone app via Bluetooth. The app allows you to send private messages, have a group chat, or share your GPS location to all goTenna holders nearby. You can also access offline maps for free via the app.
Using its own mesh networking technology, it communicates with other goTenna devices in an area to create its own off-grid network. It can communicate with other goTenna devices within a 1.8km radius; the record range is 10 miles.
You can buy goTenna in pairs. It runs on a rechargeable battery that can last for up to 24 hours of use.