Working Principle : Non-buried NPN normally open capacitive proximity switchIt could work with any kinds of bed materials, such as glasses, woods, metals, and so onIt is an auto leveling sensor for 3D Printers based on open-source.Product Description:Model: M12 capacitive proximity switchInstallation type: non-embedded Action mode: NPN normally openSize: M12 x 62mmWiring length 150mmShell nickel plated brass, detection surface ABSDetection distance: 5mm +/- 10%Lag distance: less than 10% of the detection distanceDetection object: metal, non-metal: plastic, glass, wood, liquid: water, oil, etc.Voltage: DC 6-36V Operating environment temperature: -25C-65C, no freezingUse environment humidity: 35-95%RHColour: SilverMaterial: MetalPackage Contents:1 x Proximity SensorAttention: Please remarks the 3d printer model in your order.Only the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.