Stanley Proto J6020AB 3/4-Inch Drive Ratcheting Head Micrometer Torque Wrench, 120-600-Feet Pound Calibrated to +/- 3% clockwise direction and +/- 6% counter clockwise at 20% to 100% of full scale Calibration is accomplished by manual loading the torque wrenches Manufactured to meet standard industrial torque applications, general industry, heavy equipment, and maintenance