Features: Experience superior frequency stability with 7.83Hz Schumann Waves Signal Generator, featuring programmable modulation technology adjustables from 0.001Hz to 200KHz. from ABS materials, this signal generator offer a digital circuit crystal oscillator frequency reference for enhanceds stability and strong antiinterference capabilities. for both men and women, this device for enthusiasts and professional seekings precise frequency control. for use in sleep enhancements environment or as part of advanced electronic projects, ensuring performances in various setting. With its sine Waves antennas output and 7.83Hz setting, this signal generator is tool for anyone interested in exploring the benefits of Schumann resonances. The product is plug and play. When the frequency is high, there will be a deviation of less than 1%between the input and the actual output. The sound output of the speaker is based on the frequency. At low frequencies, the human ear cannot hear it. If the speaker is plugged in and the frequency reaches the hearing ranges, there will be sound. Specifications: Materials: ABS Size:15x12.3cm/5.91x4.85inch Package Includes: 1PC Schumann Waves Generators note: Please allow 0-1cm error due to manual measurement. make sure you do not mind before you bid. Due to the differences between different monitors, the picture may not reflect the actual color the item. Thank you!