Review on Smart WiFi Door and Window Sensors - White, No Hub Needed, Wireless Design, Instant Alerts, 2.4 GHz Wi-Fi Required, Alexa and Google Assistant Compatible, Home Security by Farhad Cantu

Okay, so I hate devices that use round batteries - they're expensive and quickly drain from what I've found. This device is larger than the Wyze sensor (next to him in the picture which I should just rip off and throw away as you can't replace batteries and it no longer connects to its own sensor bridge) which it replaced but I used batteries - and in my opinion all devices should be either AAA or AA where they can - and not double-thick round nickel-sized ones. If you mount it at the top of the door, make sure the gap works properly when you glue the smaller part, otherwise it will hit the larger part when closing. The side mount is better, but we didn't want our kids messing with it. If you can handle that, you can easily do the rest with the smart home app and just tether it to Alexa. Good luck with this device - I plan to buy more of these.