This Armstrong 1/2" Drive Micrometer Torque Wrench (10 ft/lb - 150 ft/lb) is designed with an innovative linear ball bearing mechanism that improves the performance of the wrench by eliminating friction between spring and case for greater accuracy, eliminates speed sensitivity errors, and produces a "crisp audible click" over the entire range. Meets or exceeds ASME B107.14M 1994 and has an accuracy of +/- 3% CW from 20% to 100% of wrench capacity. The twist detent locking ring allows easy setting of desired pre-set torque and prevents accidental change of the torque setting while in use. Created with a lightly knurled and grooved handle provides a comfortable, non-slip grip. The ratchet head is specifically designed for torque wrenches with more material in high stress areas, enclosed with 10 degree ratcheting arc that seals out contaminants for improved performance and longer life, torque wrap designed to reduce stress on gear and pawl teeth for greater strength and durability.