Honeywell STRN-CA-02 Self-Centering Crank Arm. for the S03 and S05 Actuators Series. Crank Arms are designed open and close Damper Actuators manually and electronically. Pneumatic actuators provide proportional control of steam or hot or cold liquids in HVAC systems by operating valve assemblies. Replacement devices are available for older Honeywell actuators.