Features: * Brand new and high quality * Using high-quality materials, the product has good frequency stability; * This product can not only output 7.83Hz Schumann wave, but also incorporates programmable frequency modulation technology, which can adjust the frequency within the range of 0.1Hz~30KHz; * 2 specifications can be selected according to needs, the red square wave non-adjustable frequency is fixed at 7.83Hz, and the green standard model has various frequencies adjustable from 0.1Hz to 30000Hz; * Digital circuit crystal oscillator frequency reference, more stable and stronger anti-interference ability; * The power supply interface adopts DC5.5*2.1 interface, which is easy to use. It can work by inserting a rechargeable battery or USB charging head or other USB power supply device into the USB end. * Schumann waves themselves do not directly act on sound or video products to improve sound quality, but act on the space environment to relax the human body and mind, improve the human body's perception of sounds and images, improve human health, increase work efficiency, and relieve psychological stress. Better results. This product can not only output 7.83Hz Schumann wave, but also adjust the frequency within the range of 0.1Hz~30KHz. It is a digital circuit crystal oscillator frequency reference, which is more stable and has stronger anti-interference. Specification: Style (optional): Adjustable frequency DPBT, Non Adjustable DPBU Green standard model: Circuit board size: 15*15cm Antenna waveform: sine wave Interface waveform: 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 interface: DC5.5*2.1 Power supply voltage: 5V Rated power consumption: