I got these leak sensors to replace another brand. The app is great and the sensors are easy to link to the hub. The range of the built in radio is phenomenal and much greater than the range of the sensors they replaced. I like the batteries, too. They use two AAA batteries and the ad copy says they have a two year battery life or longer. My old sensors used a CR2032 lithium battery that I had to change every four months.
The sensors are monitored by the hub, which needs a power and internet connection. The status of the sensors is shown in the easy-to-use app. The app can also be set to send an alert by text or email to your phone. Finally, it is possible to link the sensors to YoLink's siren module (separate purchase), which I did. The siren is plenty loud and can be placed in a central location to clearly alert you.
Overall, these are a clear winner.