This 3 hours brown noise at 400 Hz delivers a deep, grounding sound designed to calm the mind and support uninterrupted sleep. The black screen eliminates visual stimulation, helping you focus entirely on rest.Brown noise emphasizes lower frequencies, making it especially helpful for anxiety, overthinking, and deep relaxation.Frequency: 400 HzDuration: 3 HoursScreen: BlackNo visuals.No talking.Just deep sound that stays.Brown Noise Sleep SoundsSound that stays.