Batteries: What kind are needed and how long do they last?

The Wi-Fi Sensor is powered with (2) AA batteries that are included with purchase and last up to 18 months.

The Sensor 2.0 is powered with (3) AAA batteries that are included with purchase and last up to 18 months as well.

In both cases, the LeakSmart app provides low battery notifications when it is time to change the batteries.