With this smart indoor siren from Netatmo you can have your existing installation with at least one Netatmo Welcome camera make it even smarter and safer. When the camera sees someone who is not expected in your house, then the siren (110dB) rages. You can't use the siren without the welcome indoor camera, so it's really meant as an extension to this!
Funny feature of the siren is that you can play other sounds in addition to the standard siren such as a barking dog, children or a vacuum cleaner. The siren itself can of course be hung up or put down somewhere as it is completely flat at the bottom / back.
If you want to expand your installation even further, then Netatmo also has the set with 3 tags to protect your doors or windows against intruders.