BriarTek Cerberus Two-Way Satellite Messaging and GPS Tracking System CerberLink lets you send and receive messages, track, drop breadcrumbs and share public messages anywhere in the world using the Iridium satellite network; 4.7 x 2.6 x 1.3-Inch/ 6.6-Ounce CerberLink connects to your iOS or Android device via Bluetooth so you can compose/send and receive/read messages when your phone has no cell service; (works with iPhone and Android) The Cerberus system knows when you are "off the grid" and will send and receive messages by satellite, when you are "on the grid" the system will let you bypass the satellite system to send and receive messages using your phone's Internet connection Patented alerting technology pushes location specific warnings to help you avoid emergencies Questions; Go to cerberus.briartek.com for more information or send us an e-mail to "support@cerbercenter.com"