This category encompasses specialized equipment for precision measurement of surface roughness on machined surfaces in manufacturing environments. These instruments quantitatively measure roughness parameters such as Ra, Rz, and Rmax on component surfaces finished through cutting, grinding, electrical discharge machining, and other processes, serving quality control and process improvement applications. The category includes stylus-type surface roughness measuring instruments, laser-based non-contact measuring devices, and portable roughness meters, which are essential measurement equipment for finish precision inspection of metal machined parts, quality control of mold surfaces, and sliding surface inspection of mechanical components. Unlike simple length measurement, these instruments are positioned as a specialized group of measuring devices that employ unique measurement technologies to quantify the microscopic surface profile irregularities.