The Freedom Alert system is a light weight, water proof, emergency pendant. This pendant allows users to program up to four numbers for the Freedom Alert to call by two-way communication. If, by chance, it does not reach any of these numbers, it will call 911. The unit will then automatically hang up and dial emergency services. It also comes equipped with the Freedom Alert's 911 forwarding feature as well. With the 911 forwarding feature, a friend or family member can simply dial 911 from their phone while still on the line. You can even sync up to four Freedom Alert pendants to one base at your home. It also has a backup battery built into the system, but a battery can last up to 6 months on a single charge. A power outlet and an active landline are all that is needed for the unit to operate.