The SMDTB14 is an optimized product that simplifies the complex procedures of previous versions. The upgraded SMDTB14 uses three buttons to set parameters. It adds four audio signal outputs, increasing signal expansion capability by four times. It features independent amplifiers, overcurrent and overvoltage protection, and high-precision low-temperature circuitry. It also includes a robust acrylic housing. Only beneficial sine wave signals are retained, removing square waves, triangle waves, and sawtooth waves that are only suitable for laboratory use. The 7.83 Hz Schumann resonance is suitable for various applications, such as overall health, improved productivity, stress relief, and aiding sleep. For more information, search for "Schumann generator" in your browser. Features: Outputs the beneficial 7.83Hz Schumann wave, adjustable from 0.01Hz to 9999Hz. Employs a high-speed DAC for pure sine wave generation. Includes four 3.5mm audio outputs with independent amplifiers. Encased in a durable, transparent acrylic shell. Compact and lightweight design for easy portability. Specifications: 1. Working Voltage: DC 5V 2. Working Current: 15-30MA 3. Power Interface: Type-C (supports TYPE-C to TYPE-C power supply) 4. Default Frequency: 7.83Hz 5. Frequency Adjustment Range: 0.01Hz~9999Hz Pure Sine Wave 6. Signal Voltage Amplitude: 3V 7. Dimensions: 104*66*18MM Color: White Material: plastic Package Contents: 1*Signal Generator