Made to work in conjunction with the Smart Indoor Camera, the Netatmo Smart Indoor Siren scares away intruders. When the camera notices someone it doesn’t recognize, it sounds a 110-decibel alarm. Not only that, but this gadget also sends an alert directly to your phone. This way, you know exactly what’s going on at home no matter where you are. This smart security system protects your home without you having to do anything, giving you peace of mind when you’re out and about. Plus, it won’t send you false alarms caused by family members, pets, or people you know. Measuring just about five inches in diameter, it fits on pretty much any wall space. And you can choose to hardwire the Smart Indoor Siren with a Micro USB cable or have it operate with batteries.