The miniature pendant allows the user to quickly contact friends and family at the push of a button. Water-resistant and voice prompted, it provides announcements during set-up, testing, battery test and full system check. Standby Emergency Battery Power consists of four rechargeable batteries that continually charge in the base station to provide up to 24 hours of standby power. Fully portable. Plug it into any standard phone jack, and you are protected. Simple set-up.