No wires. No hassle. Just reliable rain sensing that provides optimum water savings. Toro innovative wireless technology provides easy to use, advanced features for the prompt reaction when it starts to rain. With options for rain or rain/freeze sensing, the TWRS Series can save up to 30% more water than existing disc rain sensors. The patent-pending Water Conservation Mode turns the RainSensor into a smart sensor by allowing the receiver to intelligently extend the controller reset based on settings provided by the user. All sensors can be set for universally Normal-Open or Normally-Closed operation making the TWRS compatible with just about all electronic timers.