SI-LS42DSG - 

Turck SI-LS42 Series Safety Interlocking Switches
The SI-LS42 series safety interlocking switches come with guard locking capability. This makes it possible for them to be used to secure a guard (or gate) such that the hazard has time to stop before the guard can be opened. As such the guard can be located closer to the hazard making access to the hazard for maintenance easier yet still maintaining the safety of the operator.