Worldwide patent. Chrome-vanadium ratchet gear and fully heat treated handle. Guaranteed to meet ISO 6789, U.S.Fed.GGG-W686D and ANSI Spec. Factory calibrated for accuracy to within ± 3% (of reading form B107.14M. 20~100% maximum range). Window is equipped with convex for scale viewing. Operated by unique pull-push system. Torque wrenches are precision tools and are not designed for use in loosening bolts and nuts. Each set contains calibration certificate. Item Dr. Range of the Torque Length Gear Teeth Type 4932 1/4" 5~25Nm/4~18lb.ft 290mm 45T B 4933 3/8" 10~50Nm/9~35lb.ft 360mm 45T A 4934 3/8" 20~100Nm/15~70lb.ft 405mm 45T A 4935 1/2" 20~100Nm/15~70lb.ft 405mm 45T A 4936 1/2" 40~200Nm/30~140lb.ft 500mm 45T A 4937 1/2" 60~300Nm/45~220lb.ft 595mm 45T A 4938 3/4" 110~550Nm/85~405lb.ft 970mm 24T A 4939 3/4" 150~750Nm/115~550lb.ft 1150mm 24T A 4940 1" 200~1000Nm/150~730lb.ft 1250mm 24T B