The Roost Smart Battery for smoke alarms transforms your smoke or carbon monoxide alarm into a smart home device just like that. With the same form factor as a conventional 9-Volt battery, the Roost Smart Battery works with existing alarms to upgrade the safety and convenience of your home. Download the free Roost app and get alerts delivered to your Smartphone if your alarm sounds, wherever you are. No more chirps - receive low-battery notifications, before the 3 AM chirp starts. Retrofit your existing alarms without any tools, hubs or installers. Invite friends and family to monitor your alarms for increased peace-of-mind. The Roost Smart Battery lasts for more than 5 years and installs in 5 minutes. No tools, wires, hubs or professionals needed. All you need is a Smartphone and Wi-Fi. This is not your average 9-Volt battery.