YoLink Water Leak Sensor 2,1/4 Mile World’s Longest Range Smart Home Water Leak Sensor,Water Leak Detector with Built-in Siren Up to 105dB,Works with Alexa and IFTTT-YoLink Hub Required,YS7904-UC

From the brand

STATE-OF-THE-ART Smart Water Leak Detection: LoRa-based 1/4 mile open-air range, 2+ year battery life, no dependence on WiFi, device-to-device pairing provides functionality even with the loss of AC and/or internet!
ROPE STYLE water-sensing cable, 4.2 feet (1.2 meter) long, additional cables can be added, for detection in confined spaces, such as under a dishwasher, and for defining specific detection areas, such as encircling a water heater
THAT WAS EASY! Installs quickly and easily, thanks to Scan & Play QR-code scanner feature in the app, easy wall-mounting, and no requirement to plug the sensor into an AC outlet.
NO WIFI, NO INTERNET, NO POWER? NO PROBLEM! Our patented Control-D2D device-to-device pairing, over our LoRa-based wireless network, allows for devices to be paired to each other, in such a way they will continue to operate, even if WiFi is flaky, the internet goes down, or the AC power goes out!
A YoLink hub is REQUIRED! This device will not operate without a Hub, not included. Please search for B09FSS95G9 for a SpeakerHub (our audio, talking hub) or B07TQLKQLJ for the original Hub