Product details: Model KP-LJ2:  

The Plug torque tester is for compliance is checked by engaging the device, as during intended use, with the socket-outlet of a test apparatus as shown in IEC60065 Figure 11.

A device provided with pins intended to be introduced into fixed socket-outlets shall not impose undue strain on these socket-outlets. 
The balancing arm of the test apparatus pivots about a horizontal axis through the centre lines of the contact tubes of the socket-outlet at a distance of 8 mm behind the engagement face of the socket-outlet. 
 

With the device not in engagement, the balancing arm is in equilibrium, the engagement face of the socket-outlet being in the vertical position. 
After the device has been engaged, the torque to be applied to the socket-outlet to maintain its engagement face in the vertical plane is determined by the position of a weight on the balancing arm. The torque shall not exceed 0,25 Nm.