Turn the small key at the grip of the torque wrench handle using a small key ring. Then you will see the numbers in the long rectangular box of the torque wrench moving up or down. When testing the #16 rebar coupler, first turn the small key to align the scale line in the middle of the box with -80 ≤16. Then use the head of the torque wrench to clamp the rebar coupler. Press the torque wrench with an appropriate force. If you hear a “pop pop” sound, it indicates that the tested #16 rebar coupler can meet the testing requirements. Otherwise, it means that the fixing force of the steel bar rebar coupler does not meet the testing requirements. The same applies to the following situations.