Product description: Shuman wave generator, we call it Tesla wave generator and jokingly call it Xuanxue wave generator. It is essentially an extremely low frequency (ELF) electromagnetic wave. According to the multiplication of the speed of light wavelength by frequency, the wavelength of the 7.83HZ electromagnetic wave is 38000 kilometers, which is very close to the well-known circumference of the Earth, which is 40000 kilometers. In fact, Tesla waves are an inherent property of geophysical characteristics, forming an electromagnetic resonant cavity on the surface and ionosphere, and 7.83HZ is the natural frequency of this resonant cavity. When an electromagnetic wave with such a frequency is emitted, it will form a standing wave in the Earth's space and will continue to oscillate for a long time. Working mode: Power 7.83Hz extremely low frequency electromagnetic wave: 0.3mW without any sound Charging method: Equipped with a built-in 2000mA lithium battery, it can be charged using the Type-C interface commonly used on mobile phones (a mobile phone charger is sufficient, with no current limit) Red light on: charging in progress Green light on: Full Blue light flashing: emission status Light off: shutdown/battery depleted Power supply voltage:5V1A Colour:Black & Silver Material:ABS Package Contents: 1 * Schumann wave generator 1 * Type-C power cord 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.