Siemens SAS81.33U POWERMITE 599 MT SERIES SAS ELECTRONIC VALVE ACTUATOR, SR, 24V, FLOAT CONTROLSiemens SAS81. 33U Powermite 599 MT Series SAS Electronic Valve Actuator, SR, 24V, Float Control The Powermite 599 MT Series SAS Electronic Valve Actuator requires a 24V supply and receives a floating control signal to provide three position control of a valve. The spring return actuator works with Powermite 599 MT Series terminal unit valves with a 7 32 in. stroke. Additional Information Fail SafeYes Spring return functionSpring return functionality