This product is Schumann .83HZ very low frequency generator, features high accuracy and stability. High stable frequency acquisition elements: high stability pulse chip, precision correction capacitance, precision multi-loop adjustable resistor. High quality polymer batteries, with overcharged, overvoltage, overcurrent protection. There is almost no voltage ripple in the voltage supply. With work toggle switch, easy to use. Schumann wave can be applied to HIFI or sleep. Power: 12V 1A android charging cable Polymer battery capacity: 2300mah Working time: 200 days(full of electricity) Schumann wave itself is not directly acting on the sound or video products to improve the quality of sound quality, but the role of the space environment, people's physical and mental relaxation, improve the body's perception of sound and images, improve the health of the human body to improve the efficiency of work, mental stress also have a better effect. Schumann wave applied to sleep: 1. It is recommended to buy a trial, on a bedside, more than 1 meter from the human body distance. 2. The trial, plus the appropriate weight for anti-vibration treatment. 3. The appropriate use of paper cloth cloth block indicator light, remove the product at night light 4.Try it for a week and analyze seven days of experience. Colour:silver Material:plastic Package Contents: 1 x Schumann Wave Generator 1 x USB Cable 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.