The Schumann wave generator offers sine wave, square wave, and reverse square wave options. An included dust cover helps protect the circuit board. Adjustable frequency: You can adjust the frequency from 0.01 Hz to 99999 Hz for improved efficiency. Stable: The Schumann wave generator guarantees a stable frequency output, with a standard value of 7.83 Hz, a sine wave voltage amplitude of 3 V, and a square wave voltage amplitude of 5 V. Compact and portable: The Schumann wave generator is small in size, USB powered, and easy to carry at home or while traveling. Promotes relaxation: The Schumann wave generator emits sine waves, creating a relaxed and pleasant environment that promotes physical and mental well-being. Specifications Product Name: Schumann Wave Generator Adjustment Range: 0.01 Hz ~ 99999 Hz Sine Wave Signal Voltage Range: 3V Square Wave Signal Voltage Range: 5V Power Interface: DC 5.5 x 2.1 Nominal Power Consumption: <1W Antenna Waveform: Sine Wave Interface Waveform: Sine Wave + Square Wave + Inverted Square Wave (Output interface is located at the bottom left; waveforms are output simultaneously) Color: Red Material: PCB+Plastic Package Contents: 1 * Schumann Wave Generator 1 * USB Cable (Random color) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.