The SICK GRTB18-P2406S07 is a Type 4, IEC 61496-1/-2 compliant Safety Light Curtain from the high-performance GRTB series. It is engineered to provide the highest level of personnel protection (Category 4, PL e according to ISO 13849-1) around hazardous machinery. This system creates an invisible vertical curtain of infrared light beams; when any beam is interrupted, it sends a stop signal to the machine's safety relay or controller to initiate an immediate shutdown, preventing injury.