Features: It can improve the human body's perception of sound and images, improve human for health, increase work creation efficiency, and have a good effect on insomnia and mental stress. It used mini USB port power supply, generally is +5V 0.1A, and equipped with USB cable. Imported ultra-low static power consumption main control IC makes the waveform more stable. 7.83HZ pulse is output, the duty cycle is 50%, and the frequency can be fine-tuned and corrected. This product is a 7.83HZ very low frequency generator, which has the characteristics of high precision and good stability. Specifications: Material:PCB Power Supply: +5V Current: 0.1A Pulse Square: 7.83Hz Net Weight:22g Note: Please allow 1mm errors due to manual measurement. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1x Schumann Wave Generator