Limiting nail. In the vertical testing machine, the thing that can block the ejector pin is called a limit nail. Vertical fully automatic plug-in force testing machine is also referred to as fully automatic plug-in force testing machine. This machine is suitable for testing the insertion force and extraction force of various connectors. With the patented automatic centering device, a completely accurate insertion and extraction force test can be obtained, and the Chinese screen setting of the Windows window is used.