... E3Z Omron E3Z-R81 Retroreflective Photo-electric SensorPre-Wired Type , Sensing Distance 4m , PNP Transistor OutputE3Z-R81,E3Z-R81-C1E3Z-R81H ... 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 Output Omron E3Z ...