You receive: This product includes a resonance generator, an acrylic case with a small magnet, and a USB data cable. Note: The acrylic case may have a slight odor, which can be dissipated by placing it in a well-ventilated area or in the sun for 2 to 3 days. It is recommended to remove the protective film before use. This device produces low-frequency electromagnetic waves and requires the use of headphones. Adjustable frequency: Offers a frequency range from 0.01 Hz to 100,000 Hz, allowing you to customize settings for efficiency and personal preference. Default frequency is set to 7.83 Hz, with additional options including 174 Hz, 285 Hz, 396 Hz, 417 Hz, 528 Hz, 639 Hz, 741 Hz, 852 Hz, and 963 Hz. Multiple waveforms: Provides sine wave, square wave, and reverse square wave outputs, suitable for various applications in environments such as laboratories and studios. Promotes relaxation: The resonance generator emits sine waves that help create a calming environment, supporting mental relaxation and well-being. Makes a thoughtful gift for holidays such as birthdays and Christmas. Portable design: The sound generator measures approximately 5.9 x 5.5 x 1.2 inches, and the acrylic case measures approximately 6.2 x 5.8 x 1.5 inches, providing secure coverage. Its compact size and USB-powered operation make it convenient for travel and on-the-go use. Stable performance: Features a stable sine wave output with a voltage amplitude of 3V and square wave output with a voltage amplitude of 5V, ensuring reliable and accurate signal delivery. Wide application: Suitable for use in electronic testing, equipment calibration, scientific experiments, and other scenarios requiring precise signal and frequency control. Frequency range: 0.01 Hz to 3000 Hz.