PROTO 1/2"" DRIVE RATCHETING HEAD MICROMETER TORQUE WRENCH 30-150 FT-LBS W/NIST CERTIFICATE CALIBRATED TO +/- 3 IN CLOCKWISE DIRECTION AND +/- 6 IN COUNTER CLOCKWISE DIRECTION. CALIBRATION IS ACCOMPLISHED BY MECHANICAL LOADING OF EACH WRENCH IN A HORIZONTAL POSITION AND PERFORMING A THREE CLICK TEST AT 20 60 AND 100 OF MAXIMUM INSTRUMENT CAPACITY. CERTIFICATION DOCUMENTS TRACEABLE TO N.I.S.T. (NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY). MANUFACTURED TO MEET PRECISION/HIGHLY ACCURATE APPLICATIONS SUCH AS MILITARY AND AEROSPACE.