Omron E3Z-R81 Retroreflective Photo-electric Sensor Pre-Wired Type , Sensing Distance 4m , PNP Transistor ... PNP Transistor OutputRetroreflective Type (Oil-Resistant Model) , Pre-Wired M8 Connector Type , Sensing Distance 0.1 to 3m , PNP Transistor ... OutputRetroreflective Type (Oil-Resistant Model) , Pre-Wired M8 Connector Type , Sensing Distance 0.1 to 3m , PNP Transistor ...