Of course, the sophistication and complexity of hydraulic system will vary depending on the specific applications .This is also true of the individual components that comprise the hydraulic system. As an example, refer to Figure 1-17, which shows two different-sized, complete hydraulic power units designed for two uniquely different applications. Each unit is a complete, packaged power system containing its own electric motor, pump, shaft coupling, reservoir and miscellaneous piping, pressure, gages , valves, and other components as required for proper operation. These hydraulic components and system are studied in detail in subsequent chapters.