M4 thread or retaining strap
Proximity switches use sensors that respond to the object approaching them, i.e. without direct contact. Proximity switches are used in technical processes for detecting the position of workpieces and tools and to trigger safety actions. In many proximity switches, the sensors and switching mechanisms are combined in a common unit.
It is used for contactless scanning of pneumatic cylinders and similar applications. The presence of a magnetic field or Fe (iron) part triggers the pneumatic signal.
Proximity switch is in principle a 3/2-way pneumatic valve which is actuated without a contact via magnetic field or an Fe part.