Intelligent irrigation, without a sprinkler system. Zilker is small in size but packed with innovative technology. A 915MHz radio (between the bridge and each valve) provides over 2.5 times the range of Wifi. A latching solenoid uses no power except to switch states, allowing two AA batteries to last up to a year. And an axial turbine calculates flow rate, so that you can measure in gallons or inches, rather than minutes.