The Siemens 656-599 1/2″ Replacement Actuator is a high performance replacement secured to ensure precise control in HVAC systems. Operated between 3 to 8 PSI at a CV of 2.1, this actuator efficiently and reliably serves as a means to manage efficient, reliable air flow. It fits well into systems with 1/2" valve size and so can be used for several HVAC applications. #Siemens #656-5... https://www.partshnc.com/656-599-siemens-building-technology-mite-rplmt-top-12-3-8psi