Features: Made of quality material, which is durable and for long time use. When it operate in the air, no crackling sound, but the temperature is very high, can easily ignite paper, plastic, even very fine wire. For middle school science experiments, electronic instruments, negative ion generator, science and small production. The transformer primary has two windings, one main winding and one feedback winding. The two thick and fine coiled copper wires are the positive poles, which are respectively the main winding tail and the feedback winding head, connected to the positive poles of the power supply. Specification: Input Voltage: 3.7V-4.2V Current: ≤ 2A Output Voltage: ≤ 15KV Input Current: ≤ 0.4A High voltage ignition distance: 0.5-1cm/ 0.2-0.4in Size: Approx. 25*20*15mm/1*0.8*0.6in Package List: 1 * High Voltage Pulse Generator Note: The transformer's high-voltage winding is wound on the inner layer, which is a segmented framework and encapsulated by epoxy resin. The low-voltage winding is on the outer layer. Please do not mistake the winding way of the high-voltage winding and low-voltage winding of this transformer.