Aquapro Screw-In 10k Water Temp Sensor works with Aquapro models ECO600, VIGOH77, PRO1100, PRO1300, PRO1400, and PRO1400HC manufactured in our about 2013. AHN style units have 4 buttons for control below digital temperature display. Models include Eco600, VIGOH77, PRO1100, PRO1300, PRO1400, and PRO1400HC Installed in water inlet pipe inside heater to measure water temperature entering heater. Sends temperature information to main board for proper heating of water. Built in spade connector for easy electrical connection to main control board. 6 foot total length with wire.