Enerpac E391 is High efficient planetary gear set that achieves high output torque from low input torque with a Square Drive of 3/4" and Maximum Torque Output of 1200 ft. lbs. The Multiplier output accuracy ± 5% of input torque having Reversible, tighten or loosen bolts. This Multiplier is a Reaction bar type. The E300 and E400 torque multiplier series replaceable shear drives provide overload protection of the internal power train (one replacement shear drive is included).