High quality polymer batteries, with overload, over-voltage and over-current protection. There is almost no voltage ripple in the voltage supply. Stable high-frequency acquisition elements: high-stability pulse chip, precision correction ability, precision multi-loop adjustable resistance. This product is a Schumann.83HZ very low frequency generator, with high accuracy and stability. With working rocker switch, easy to use. The Schumann wave can be applied to HIFI or sleep., Manufacturer: Niniang