Usage Tips:The operating principle of the machine is based on two counter-rotating discs made of insulating material. Each disc has several metal segments attached to it, called sectors. As the sectors pass, they induce a fee imbalance on another. This imbalance is drained to the collecting electrodes. 1. Set the gaps between the two electrodes to about 1-2 inches. 2. Turn the handle slowly first and increase the rotation. 3. Once the voltage of the capacitor is enough to overcome electrostatic breakdown at the electrodes, discharge will take place and spark is seen or heard. size:33*10.5cm Material:Wood + metal colour:Silver Package Contents: 1 * Electrostatic Generator 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.