Valve Actuator:

An actuator operates the stem and disk assembly. An actuator might be a manually operated manual lever, handwheel, solenoid operator, motor operator, pneumatic operator, or hydraulic ram. Within some designs, the actuator is supported through the bonnet. Alter designs, the yoke mounted to the bonnet supports the actuator.

Except for certain hydraulically controlled valves, actuators are outside of the pressure boundary. Yokes, while used, are always outside of the pressure boundary.