Sonnet
This is a super advanced walkie-talkie
Screenshots
Hunter's comment
Sonnet let's you connect to your friends even without network signal and internet. You can send instant message, voice recordings, image data and GPS coordinates. With just 3 simpl steps you are on the go : Connect your smartphone to the WiFi on the sonnet, open the browser and visit https://app.sonnetlabs.com/ and you're ready to chat! When you are travelling abroad or in a dead spot this is very useful when you are in group, stay connected to each other.
Features:
• Point-to-point range between two Sonnet devices is 5 km (3 miles) to 15km (9 miles, if there is line of sight)
• Mesh Networking 80 km (50 miles) you can comnect to other sonnet devices
• Battery last up to 36 hours, 4000 mAh
• Built-in offline maps
• You can connect external antenna using SMA connector for better connection range
Link
Contributors
Hunter: 
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