Feature: 1. This product is made of high quality materials, the use of low temperature drift crystal oscillator and high precision DAC special chip, the product has good frequency stability 2. This product can not only output 7.83Hz Schuman wave, but also add programmable frequency modulation technology, can adjust the frequency in the range of 0.01Hz-100000Hz 3.2 kinds of specifications, there are 2 kinds without shell and with shell can be selected according to demand 4. Digital circuit crystal frequency benchmark, more stable, stronger anti-interference 5. The power supply interface adopts the Type-c interface, which is easy to use and supports Type-c to Type-c power supplies. Product Schuman wave itself is not directly acting on sound or video products to improve the sound quality, but the role of the space environment, so that people's body and mind can be relaxed, improve the body's perception of sound and images, improve the health of the human body work efficiency, relieve psychological pressure also has a good effect. The product can not only output 7.83Hz Schumann wave, but also adjust the frequency in the range of 0.01Hz-100KHz, digital circuit crystal oscillator frequency reference, more stable, stronger anti-interference, using low-temperature drift crystal oscillator and high-precision DAC dedicated chip, can precisely output frequency and pure sine wave. Product parameters: Working voltage: DC 5V (DC 4-15V) Power interface: Type-c (Support Type-c to Type-c power supply) Default frequency: 7.83Hz Adjustment range: 0.01Hz-100000Hz pure sine wave Signal voltage amplitude: 3V Tips: The product may be updated constantly ,Due To Different Batches, The Actual Product May Have Slight Differences Or Color Differences, Which Does Not Affect Use Set: A With shell or B without shell Material: PCB colour: As shown Package Contents: 1 x Schumann Wave Generator Only the above package content, other products are not included. Note: Light r