Crystal singing bowls at 432Hz for kids who need a quiet wind-down before sleep. Slow, ringing bowl tones drift and fade for four and a half hours, a soft and spacious sound that suits a calm bedtime or a rest after a big day. Press play once the bedtime routine is done and keep it at a low, comfortable level in the background. Keep the volume low and the speaker away from the bed. (A relaxation aid, not a medical treatment.)