Note: the acrylic case may have a glue smell, which can be dissipated by placing them in the sun or in a ventilated place for 2 to 3 days, and it is recommended to remove the film before application; It is a low-frequency electromagnetic wave that requires headphones to be heardAdjustable Frequency: with an adjustable frequency range of 0.01 to 200000Hz, our sine wave generator allows you to set according to your needs for increased efficiency and personalization; The default frequency is 7.83Hz, and it can also be adjusted to 174Hz, 285Hz, 396Hz, 417Hz, 528Hz, 639Hz, 741Hz, 852Hz, 963Hz, and more, providing a more accurate user experienceMultiple Waveforms: our sound frequency generator resonator provides multiple waveforms, namely sinusoidal, square wave, and inverted square wave, which is suitable for wider applications and various environments, such as laboratories and studiosPromote Pleasure and Relaxation: the adjustable schumann resonance generator can emit sine waves to create a relaxing environment, improving the state of your mind and enhance your well being; It'll also be a warm gift for friends and families on birthday, Christmas and morePortable Size: the sound frequency generator measures about 5.9 x 5.5 x 1.2 inches, and the acrylic box measures about 6.2 x 5.8 x 1.5 inches, which can cover the frequency generator well, and its small size and USB powered design, making it easy to carry and applied at home or when travelingColor: As ShownMaterial: Metal+PlasticPackage Contents:1 x Adjustable Schumann Sine Wave Resonance Generator with Acrylic Case1 x USB Data Cable1 x Pen