The Siemens S55174-A203 STP121.65L10 actuator is an electrothermal actuator specially designed for the control of small valves in heating systems, cooling ceilings and air after-treatment units. This actuator operates with the plunger retracted in the normal state, which enables reliable 2-point and quasi-static control. The integrated position indicator provides a clear view of the current status of the actuator, making it easier to monitor and control the systems. The actuator is versatile and can be mounted on various valves, including the Siemens VVP47, VXP47 and VMP47 models, as well as on valves from other manufacturers. With its electric actuator design and the manufacturer's commitment to sustainability, as evidenced by the RE100 initiative, this actuator provides an efficient solution for modern heating and cooling systems.