This series features sturdy torsion beam design for dependable long life and accuracy. The small frame model offers working ranges from 3 in. lbs to 50 ft lbs in 1/4 and 3/8 in. drives. The large frame model continues from 100 ft lbs through 2000 ft lbs with 1/2, 3/4 and 1 in. drives. Accuracy of both series of plus/minus 3 percent meets or exceeds ASME standards, ISO 6789 bi-directionally from 20 to 100 percent of scale. All wrenches supplied with a N.I.S.T. traceable certificate of calibration.