An assembly is set of manufactured parts or components that work together in unison as one mechanism or device. A gauge is a device used to make measurements or in order to display certain dimensional information. A wide variety of tools exist which serve such functions, ranging from simple pieces of material against which sizes can be measured to complex pieces of machinery. Depending on usage, a gauge can be described as a device for measuring a physical quantity, for example to determine thickness, gap in space, diameter of materials or pressure of flow or a device that displays the measurement of a monitored system by the use of a needle or pointer that moves along a calibrated scale. Specifications. Height 3.9 in.. Width 15.1 in.. Length 12.15 in.