Specialized measuring instruments for accurately measuring and managing tightening torque of bolts and nuts, and torque values of rotating shafts. Used for tightening management in assembly processes at manufacturing sites, rotational torque monitoring of mechanical equipment, and tightening torque inspection in quality assurance. Includes diverse products such as digital display torque wrenches, torque meters, rotational torque meters, and static torque meters according to measurement methods and applications. Essential for critical fastening component management in automotive and aerospace industries, assembly quality control of precision machinery, and torque diagnosis of motors and reducers in equipment maintenance. Clearly different from force gauges and pressure gauges in measurement targets, specialized for measuring rotational force and torsional force.