This 3 hours white noise at 400 Hz is designed to create a steady, neutral sound environment for sleep, focus, and relaxation. The black screen removes visual stimulation, helping your mind settle naturally.White noise helps block background sounds, reduce distractions, and support uninterrupted rest. Ideal for studying, meditation, anxiety relief, or overnight listening.Frequency: 400 HzDuration: 3 HoursScreen: BlackNo visuals.No talking.Just white noise that stays.Brown Noise Sleep SoundsSound that stays.