goTenna

goTenna powers robust, secure, decentralized communication networks compatible with your phone.
The goTenna app works with our devices to enable 100% off-grid messaging, GPS, and other fantastic features like ‘push for help’.
Download the app, pair to your phone via Bluetooth, and start communicating with other users without cell service or wifi. Plus, download free offline maps, share your location, ‘hop’ messages via other users to extend range, and keep your group connected on any adventure!

Major app features:

goTenna (free to download and use):
- Send & receive messages
- Share locations on free offline maps
- Instant transmission within range
- Encrypted 1-to-1 & group messaging
- Delivery confirmation & message retry (1-to-1 chats only)
- “Shout” broadcasts to all goTenna user’s within range
- Emergency broadcast ‘push for help’ mode with programmable emergency message
- Upgradable via firmware & software updates
goTenna Plus (in-app subscription; optional upgrade for just $9.99/year):
- Rich offline topographic maps
- Location tethering (automatically share locations with trusted contacts)
- SMS network relay
- Trip statistics
- Group message delivery confirmation (goTenna v1 only)
For all goTenna Plus subscriptions:
- Payment will be charged through your iTunes account at confirmation of purchase.
- Subscription renews automatically unless cancelled at least 24 hours prior to the end of the subscription period.
- Account will be charged for renewal within 24-hours prior to the end of the current period for $9.99.
- Subscriptions can be managed and auto-renewal can be turned off by going to Account Settings after purchase.
- Any unused portion of the free trial period will be forfeited upon purchase of a subscription.

Terms of use
http://www.gotenna.com/pages/terms-of-use-apps