This document discusses valves and valve components. It describes common valve types including check valves, relief valves, control valves, and isolation valves. It also discusses valve motion types, actuators, and valve components. Actuator types covered include manual, electrical, pneumatic, hydraulic, and smart positioners. The document also provides information on proportional valves, servo valves, solenoid valves, and auxiliary components used in pneumatic control systems like filters and boosters.