As a side note, the alarm should be tested weekly to ensure that it is working properly. The app user interface allows you to can add the Roost battery which is the smart part of the alarm to the app by tapping Add new and selecting Smart battery, choosing the location of the device, connecting to the local WiFi network and starting the setup process which will guide you through preparing the battery by pulling the tab, locating the speaker on your phone, turning up the volume and let the phone and the battery ‘speak’ to each other to establish the connection. Next, the app will let you know if everything is fine with your device and, by selecting the menu, you can configure the Profile, Change the Password, set up Invitations add other people, so they also receive notifications when the alarm gets triggered, read info About the device, Logout or Delete the Account. Also, by tapping on one of the installed alarms, you can check the Activity, view the Alarm Information, Change Location and Name, read Technical Information or Delete. Note: Inside the package, you can find the Roost RSA 400 Smoke/Fire/CO/Natural Gas Alarm, the Roost Smart Battery, the Quick Connector and the User Manual. First Alert is definitely one of the most experienced American company when it comes with developing safety products has gathered more than 50 years of experience, but, with the rapid development of the IoT products and the emergence of full fledged smart homes which get more and more complex over the years, First Alert had to adapt to the new market and create its own line of smart smoke and CO detectors to rival the popular Nest Protect. This way, it came into existence the First Alert 2 in 1 Smoke Detector and CO Alarm which has some new technologies implemented such as compatibility with Z Wave products. I wouldn’t really call the Nest Protect an elegant device since for me, it looked more like a wireless speaker, but there is no doubt that it did take a step into the right direction when it came to the aesthetic value of smoke detectors. The Onelink took inspiration and adopted a similar design, but the cheaper First Alert 2 in 1 Z Wave remained humble, featuring an octagonal rugged plastic case, lacking the flashy circular LED light, but still being equipped with everything one would expect from a smoke and CO alarm. So, on the front of the device, there is a fairly large Test/Silence Weekly button, a Power/Smoke Alarm LED and a CO Alarm LED light. On the lateral side, towards the front, there is a sliding compartment where you can enter or replace the batteries simple AA.