Using high-quality materials, the product has good frequency stability; This product not only outputs 7.83Hz Schumann waves, but also incorporates programmable frequency modulation technology, which can adjust the frequency in the range of 0.1Hz to 30KHz; Digital circuit crystal oscillator frequency reference, more stable and stronger anti-interference; The power interface adopts DC5.5 * 2.1 or Micro-USB interface, which is convenient to use. The USB end can be plugged into the power bank, USB charging head, or other USB powered devices to work. Parameter: Antenna waveform: sine wave Interface waveform: sine wave+square wave+inverse square wave (the bottom left corner is the output interface, and the waveform is output simultaneously) Power supply interface: DC5.5 * 2.1 Power supply voltage: 5V Rated power consumption:Less than 1W Default frequency: 7.83Hz Adjustment range: 0.1Hz~30000Hz Sinusoidal signal voltage amplitude: 3V Square wave signal voltage amplitude: 5V Circuit board size: approximately 15 X 14CM Colour:Black Material:ABS type:A: with case/B:without case Package Contents: 1 set of Schumann wave generator 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.