Characteristic: 1:In service,the output torque value is on all fours with the pre-setting torque value. 2:Environment,man-induced factor,and method of operation are unacted on its stability. 3:Forward&backward pre-setting torquevalue,install and take down bolt and nut safely and precisely. 4:Forward&backward ratchet design,install and take down quickly. 5:With replaceable connector.