Proximity Sensor or Switch:
Proximity sensor auto leveling can help to avoid your 3d printing nozzle hit the heat bed or prints.
Dimension: 8*51mm
Voltage: DC 5V
Theory: Inductance Sensor
Detection distance: 2mm
Output current: 200mA
Polarity: NPN
Ouput Status: Normally Open
Detect Object : Iron 15*15*1mm
Response frequency: DC:0.5kHz AC:25Hz
Wire type: 3 wire type (Brown, Blue, Black)
Cable length: 1.2m