This body-worn receiver vibrates upon receiving signals from Silent Call transmitters, and vibrates again when the user pushes the correct button. A telephone transmitter is included for notification when there's an incoming call. The receiver has four push buttons and braille letters. Five year warranty. Features: Range up to 100 feet Transmitter included for notification of phone/TTY calls Rechargeable 9V battery included Battery charger included (one year warranty) What else do I need to make this work? This is a complete system that includes all the items necessary for notification.