This product not only outputs 7.83Hz For Schumann wave but also adds programmable frequency modulation technology.The frequency digital circuit crystal oscillator frequency reference can be adjusted within the range of 0.1HZ-30KHz, which is more stable and has stronger anti-interference!Instructions:Take out the USB cable provided with the product and connect the round hole end to the circuit board.The USB end is plugged into a power bank or USB charging head or other USB powered device to work;For specific adjustment methods, see the text of the main picture.Specifications and parameters (adjustable)Circuit board size:15*15cmAntenna waveform: sine wave interfaceWaveform: sine wave + square wave + inverted square wave (the lower left corner is the output interface, and the waveforms are output at the same time)Power supply interface: DC5.5*2.1Supply voltage: 5V Rated power consumption: