5-24VDC/6-36VDC Hall NPN Sensor,3-Wires Normally Open Hall Effect Sensor Proximity Switch with Magnet: Amazon.com: Industrial & Scientific
Amazon.com: 2pcs DC 5V NPN NO M12 4mm Sensor LJ12A3-4-Z/BX Inductive Proximity Sensor Switch for 3D Printer CNC Z Probe auto Bed Leveling : Industrial & Scientific