Amazon.com: 4 Set Proximity Switch 8mm Dia Inductive PNP DC 3 Wire Sensor, Fast Response, Metal Detection, LED Indicator, IP67 Waterproof, Oil Proof 4 Set Proximity Sensor Switch : Industrial & Scientific
Banner Engineering QS18VP6R SENSOR; PHOTOELECTRIC; RECEIVER; INFRARED; RANGE 20 M; PNP: Amazon.com: Industrial & Scientific