Features: Experience enhanceds relaxation and stress relief with GHHZ4817XR21 Schumann waves Generator, featuring low frequency 7.83Hz pulses and high precisions components for stable performances. Engineered with precisions calibrated capacitors, multiple adjustable resistors, and USB C connectivitys, this portable device optimizes sound visual perception while promoting mental calmness. for insomnias sufferers, high pressure professional, or wellness enthusiasts natural solution to improve focuses during work, meditations, or leisures activity. Use pulse generator home, in offices, or during meditations to create soothing environment that enhanceds productivity and emotional balance. from PCB materials, this Schumann waves device delivers friendly energy modulation for long stress management without electromagnetic interferences. Specifications: Material: PCB Model: Schumanbo generator spirals diameter: 82mm/3.22inches Power supply method: Power supply from Type C interfaceS Power: 1watt Resonant frequency: 7.83Hz (adjustable around 10Hz) Working mode: 7.83Hz extremely low frequency electromagnetic waves, silents Overall size: 82mmx100mm/3.22x3.93inches Package Includes: 1PC Schumann waves Generator note: Please allow 0-1cm error due to manual measurement. make sure you not mind before bid. Due to the differences between different monitors, the Pictures may not reflect the actual of the item.