Yale AC-PBX Powered External Siren - Sync Alarm Accessory - Mains Powered, UK 3 Pin Plug, 104 dB Siren, Tamper Alarm, 200m range The Yale Sync Powered External Siren is an accessory of the Yale Sync Smart Home Alarm (NOTE: This product does not work with EF and SR alarms) Sync Powered External Siren The Yale Sync Powered External Siren is easy to pair with your Yale Sync Smart Home Alarm. Tailored for your needs, the Yale Sync Powered External Siren is the ideal visual deterrent for arming your home and improving your home security for enhanced peace of mind. Simply plug into the mains and connect to your Yale Home App through your phone, tablet or Apple Watch for quick, easy installation, set-up and control. Check in from anywhere in the world and receive alerts and real-time notifications when your alarm is triggered. The handy geolocation feature reminds you to set the alarm when you're leaving home, giving you one less thing to worry about. Powered by a 12v power supply, the siren generates 104db of noise, projectable over a 200m range, with tamper alerts sent directly to your phone/smart watch. No need to change batteries* or worry about power failure, as the Siren comes with a built-in backup battery powered generator for greater reliability.