The Johnson Controls VA9104-IGA-3S Electric NSR Valve Actuator with Time Out is a small and full-featured device for controlling valves in HVAC systems. A 0-10VDC signal is used for positioning of the related valve, which controls the flow of water or air in the HVAC system. https://www.partshnc.com/24v-nsr-wtime-out-35inlb