La Crosse Alerts Mobile 926-25004-WGB Add-On Sensor Only with WaterLeak Probe for existing La Crosse Wireless Monitor Alerts Mobile system Detectors moisture from any water leak, measures ambient air temperature and humidity Transmits to gateway in 200 ft. range Receive e-mail and text alerts for temperature and humidity, connection loss and low battery Internet and network router required (not included) Requires two AAA alkaline battery (not included) Detectors moisture from any water leak, measures ambient air temperature and humidity Transmits to gateway in 200 ft. range Receive e-mail and text alerts for temperature and humidity, connection loss and low battery Internet and network router required (not included) Requires two AAA alkaline battery (not included) Text and E-mail Alerts first 3 months FREE; 1 year subscription available after for $11.88 yearly ($0.99 per month), kindly refer the user manual given below for troubleshooting steps.