A cylinder or fluid motor that converts hydraulic power into useful mechanical work. The mechanical motion produced may be linear, rotary, or oscillatory. Operating pressures range from a few pounds per square inch gage (psig or lb/in.² gage) to several thousand, but usually are about 500–5000 psig (3.4–34 megapascals). Sizes vary from 0.2-in.² (1.3-cm²) linear actuators capable of a few pounds of force to extremely large linear or rotary actuators capable of exerting hundreds of tons of force. Operation exhibits high force capability, high power per unit weight and volume, good mechanical stiffness, and high dynamic response. These features lead to wide use in precision control systems and in heavy-duty machine tool, mobile, marine, and aerospace applications.