9. HiLetgo 2pcs NJK-5002C Hall Effect Sensor Proximity Switch NPN 3-Wires Normally Open. Features : NJK-5002C Hall Effect Sensor Proximity Switch. Model: NJK-5002C. Supply voltage 5-30VDC. Detection distance 10mm (effective detection distance 0-10mm) Factor Diameter: 12MM; Thread length: 12MM; Overall Length: 37MM.. "/>