The Somfy Protect Indoor Siren is an extension for your Somfy One, Somfy One + and Somfy Home Alarm. At the moment that a burglary is detected, a sound signal of 110 dB will sound. The sound switches off automatically after 3 minutes. Of course in the meantime you have already received a notification via the app on your smartphone (iOS and Android). Does the burglar think about sabotaging the siren? Then he has bad luck. The siren is equipped with tamper detection. The siren operates on 4 alkaline D batteries. When they are nearly empty, you will receive a notification via the app. So you never stand surprises.