These switches, termed endstop and limit switch, are placed on the axes of the 3D printers, allowing the system to stop at the end of the axis.
The mustache switch placed on the tiny card is mechanically closed in a small reaction and sends it to the control card. In this case, it is understood that the axis comes to the end and the movement on that axis is pointed.
The 4-pin DuPont cable is also included for easy connection in the product. The other end of the cable, which is a JST 4-pin connector, has a single female end.
It can be used with many 3D printer control cards, especially Ramps.