1. Utilizing Tesla coil principles, this high-voltage module outputs a fierce discharge with high efficiency and compact size. Simple to integrate, it requires only a switch and a battery connection. Ideal for applications needing a robust high-voltage pulse. 2. Flexible power options include a single 3.7V lithium battery or two 18650 batteries in series. For optimal performance, use batteries with a capacity over 2000mAh, removing any existing protection board from idle mobile phone batteries. 3. The module accepts an input voltage of DC 3.6-6V and boosts it to a high-voltage output of DC 20000V. Connections are straightforward: red for positive and green for negative input; output cables maintain the same color coordination. 4. Perfect for educational purposes in high schools or for DIY electronic projects. This 20kv boost step-up module can also serve as a negative-ion generator or a high-voltage source for various scientific and experimental applications. 5. To ensure safety and equipment longevity, avoid using the high-voltage module without a load. Set a proper distance for the high-voltage output line relative to the battery capacity, which affects the arc's reach and intensity in high-pressure applications. Due to different batches, there may be differences in product appearance and printed text, which will not affect use. Colour:Black Material:Metal Package Contents: 2 * high voltage transformer Only 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.