and high qualityWhen a current is passed through the coil, a magnetic field is generated around the coil. This additional magnetic field can generate an external force to the upper permanent magnet, or push or suck.By adjusting the magnitude and direction of the current flowing through the coil, the force can be adjusted to generate Stable magnetic suspension.Made of high quality material, thus it is durable.Outside Diameter: app.19mm/0.75inHeight: app.12mm/0.47inColour:brownMaterial:MetalPackage Contents:5 x Magnetic Levitation CoilOnly the above package content, other products are not included.Note: Light reflection 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.