Check the listing for details. Non-adjustable 7.83Hz For Schumann Wave Frequency Pulse Generator Multi-mode USA. Condition: New. Listed at 17.78 USD. Red Square Wave Non-adjustable Frequency On Sale ! Description:Wave itself is not directly acting on the sound or video products to improve the sound quality, but the role of the spatial environment, so that the human body and mind to relax, improve the body's perception of sound and images, improve the body's health work efficiency and relieve psychological stress also has a better effect. The product can output 7.83Hz wave, digital circuit crystal oscillator frequency reference, more stable, stronger anti-interference. Product features:1. using high quality materials, the product has good frequency stability; 2. This product can output 7.83Hz wave 3. Red square wave non-adjustable frequency fixed at 7.83Hz 4. digital circuit crystal frequency reference, more stable, stronger anti-interference; 5. Power supply interface using DC5.5 * 2.1 interface, easy to use, USB end plugged into a rechargeable battery or USB charging head or other USB powered devices can work. 6.Qty:2pcs Product parameters: Red non-adjustable model:Circuit board size: 10 * 10cmWaveform: square wavePower supply interface: DC5.5*2.1Power supply voltage: 5VRated power consumption: