Feature: 1. STABLE AND EFFECTIVE: The size of the schumann resonance generator is 16.5x13x3.5cm, and the frequency of ultra low frequency pulse wave is more stable. The specific ultra low frequency wave of 7.83Hz is helpful to improve sleep, relieve fatigue and restore physical and mental health 2. SUITABLE CONTAINERS: Schumann resonance generator is suitable for filling water with glass, porcelain, iron, etc. Aluminum, copper and other products can not be used, because aluminum, copper and other products can not let the low frequency of 7.83HZ through the container 3. BENEFIT TO HEALTH: The schumann wave generator benefit people physical and mental relaxation, improve body perception of sound and images, and improve health of human body 4. ACCURATE AND STABLE: Ultra low frequency schuman wave generator has high accuracy, good stability, can improve work efficiency, reduce mental pressure 5. WITH INDICATOR: The schumann wave generator has an operating status indicator(red, green, or blue with frequency blinking) so that you can clearly see operating status Specification: Item Type: Schumann Resonance Generator Charging Method: 1 x Rechargeable lithium battery 2000mA, using the common Type C interface of mobile phones to charge Power Voltage: 5V 1A Frequency: 7.83HZ Size: Approx. 16.5 x 13 x 3.5cm / 6.5 x 5.1 x 1.4in. Package List: 1 x Schumann Wave Generator 1 x USB Cable