Features: 7.83HZ extremely low frequency pulse generators helps to improve sleep, relieve fatigue and restore physical and mental for health. Imported super low statical power consumption main intelligent chip is adopted, and the ultra-low frequency pulse ripple frequency is more stable. Output 7.83HZ pulse, duty cycle is 50%, frequency can be adjusted and corrected, and it has the characteristics of high precised and good stability. Mini USB ports power supply, generally +5V 0.1Amp, comes with USB cable. It can improve the human body's perception of sound and images, improve the efficiency of work creation, and have a good effect on insomnial and mental stress. Specifications: Product Name: FM783 Schumann Waves Pulse Generators Material: Printed Circuit Board Package Includes: 1x FM783 Schumann Waves Super Low Frequency Pulse Generators 1x USB Cable note: Please allow 1-2cm errors due to manual measurement. Please allow for slight color differences due to different display resolution.