Features The 7.83 Hz very low frequency Schumann wave generator features high accuracy and stability with MSDS certificate. The high-stable frequency detection parts include a high-stable pulse chip, accuracy correction capacitance and multi-loop adjustable resistor. And high-quality polymer batteries are equipped with overcharge, over-voltage and over-current protection. There is almost no voltage ripple in the power supply. With working toggle switch, easy to use. Schumann waves can be applied to HiFi or sleep. The rechargeable model is small and portable and comes with a 20cm charging cable. Newly optimized circuit designs and gold-plated starting circuit. Function: 1. Schumann Wave itself does not directly affect sound or video products to improve sound quality, but the role of the room environment, relaxing people's bodies and minds, improving the human body's perception of sound and images and the Improves human health, improves work efficiency and psychological stress, and also leads to better results. 2. Used for audio-visual rooms, bedrooms, offices, innovative rooms, tea ceremonies and truth realization rooms. Specification: Item Type: Ultra Low Frequency Pulse Generator Size: approx. 68 x 52 x 12 mm/2.7 x 2 x 0.5 inches (length x width x height) Power supply: 5V micro USB charging cable for Android interface Battery: polymer lithium battery, capacity 1200 mAh Service life: Charging current: 250 mA Full charging time: approx. 6 hours Working current: 7MA Fully charged: approximately 200 hours (168 hours per week) Charging cable: approx. 20 cm Package list: 1 x Ultra Low Frequency Pulse Generator, 1 x USB Cable, 1 x Screwdriver Note: 1. Original imported electronic core components. It is recommended to use multiple units spread out as the effect is more noticeable.2. Do not tear off the protective film, disassemble it or touch the components individually when testing the product. The high stable frequency is strictly adjusted and tested in the factory.3. Please note that the new and old type of this product will be shipped randomly. Before ordering, make sure you don't mind. Package List 1 x Ultra‑Low Frequency Pulse Generator 1 x USB Cable 1 x Screwdriver