The components, products, and small systems that are the objects of design projects for manufacture as salable items or that comprise portions of a larger system have now been identified and their specifications determined, as explained in the previous chapter. For example, a gear or a resistor is a component that may be needed; a variable-pitch pulley speed reducer or an amplifier is a product or possibly part of a larger system; and a transmission system or a public address system can be recognized as a small system. Design methods for each of these items are known or may be devised from the knowledge already in the engineer’s tool kit. The task of the designer now is to decide every detail of these devices so that the device may be made in such a way that the specifications are met. These details include dimensions, power ratings, materials, alloy numbers, tolerances, specifications of components used in a system, and so forth. We shall use the term “design parameter” to designate the value or other identifying features for each of these details.