Taco Zone Valve Controls work with two, three or four-wire zone valves. Fully fuse protected, they also include two isolated end switches and built-in priority protection. The contractor friendly PC board layout eliminates the problems caused by incorrect wiring and the unfinished look of conventional zone valve installations. The sturdy screw connections add additional reliability, while the external indicator lights provide instant diagnostic feedback, reducing installation time. All Taco Zone Valve Controls are UL listed and carry an extended 3 year warranty