The VOICE ALERT SYSTEM-6 is the latest passive infrared motion detection system with an annunciator. Featuring wireless PIR sensors transmitting to a remote reciever with a built-in speaker, this system will alert you of motion using your own voice and trigger other devices using one of the four relays on the base station. The system comes with one base station and one PIR sensor. The PIR sensors are weatherproof, feature adjustable sensitivity and versatile mounting options. Instead of a generic alarm, you can record your own alerts using your own voice. For instance, if your sensor is mounted to detect motion on your driveway, you can have an alert programmed that says "Someone is in the Driveway" and one of the relays can activate a security light. Up to six sensors can be monitored by one base station and you can have multiple base stations in one system so you can hear what is going on no matter where you are in your house. Each sensor can wirelessly transmit up to 300 feet through walls and up to 1000 feet if used in an open space. Additional wireless PIR sensors are sold separately.