Serene Innovations CA-DX CentralAlert Door-Bell Knocker/Sensor

Key Features: Mnfr. Part #: CA-DX Detects the vibration of your existing door bell, door chimes, door intercom announcer or the knocking on your door, it then sends a signal to trigger the CA-360 to alert you Simple to install with adjustable sensitivity to avoid false alarms 2.5mm Jack for direct connection to your existing doorbell/door chime Advanced Technology: 2.4 Ghz Smart-Code Operating range: Up to 200ft, open space - actual distance varies according to house construction Battery type: Two AA size alkaline Battery life: up to 10 months Operating temperature: + 10 to +30°C Special Order/Lead Time required