Features Stable Performance --- Adopting high stability pulse chip, accuracy correction capacitor, accuracy multi loop adjustable resistor, and display capacitor to ensure high work accuracy. Circuit Protection --- The 7.83HZ ultra low frequency generator has high accuracy and good stability, with overcharge, overvoltage, overcurrent protection, and no voltage ripple. Multiple Functions --- Schumann wave can help people relax physically and mentally, improve the body perception of sound and image, improve work efficiency and mental state. Power Supply Method --- The schumann wave generator has built in 850mAh polymer lithium battery, the Micro USB interface for charging, making it easy to use anytime, anywhere. Applicable Scenes --- The schumann resonance pulse generator is widely used in daily life, suitable for nighttime sleep, daily relaxation, meditation, massage, and fitness scenarios. Specification: Item Type: Schumann Wave Generator Material: PCB Product Size: Approx. 68 x 52 x 12mm / 2.7 x 2 x 0.5in Power Supply: 5V Micro USB Charging Cable for Android Interface Battery: 1 x 3.7V Polymer Lithium Battery, Capacity: 850mAh (built in battery) Usage Time: Charging current 250mA, about 6 hours to fully charge, working current about 7MA, can be used for about 200 hours (168 hours per week) when fully charged Package List:1 x Schumann Wave Generator 1 x Data Cable1 x Storage Box Note:Do not tear off the protective film, disassemble and touch the components when trying the product. Package List 1 x Schumann Wave Generator 1 x Data Cable 1 x Storage Box