After an unfortunate accident with an ice maker water line, it's a good idea to have water leak alarms where you can. Not to knock the ones I have that require AC adapters (they have audible alarms too, this one is wifi only) but for the price you can't beat what this thing offers--true wireless water leak security. It was a breeze pairing it with the Smart Home app on my phone, and the test resulted in an instant notification on my phone of the leak. I may get more of these for 3 other areas of the house. They take 2 AAA batteries and are supposed to last up to a year. We will see.