The SLW1 weather station provides rain and freeze sensing to prevent watering during periods of rain and freezing weather. The rain override will stop watering after the selected amount of rain is received (factory setting is 1/8 inch). Available settings are 1/8 inch to 3/4 inch (3 to 19 mm) Using the lock tab, select the desired setting. The SLW1 weather station freeze sensing function will prevent watering when the outside temperature drops below 37 degrees Fahrenheit (1.5 degrees Celsius). Watering can resume when the temperature increases above 37 degrees F (1.5 degrees Celsius). The SLW1 weather station is designed for years of maintenance-free operation. The SLW1 does not utilize any onboard power source. Operational power is provided from the controller. To be used with Weathermatic SmartLine Controllers. Maximum controller to weather station distance is 200 feet. For installations requiring greater distance, use the SLW15 or SLW10 weather stations.