This sleep trainer teaches your child about day and night. Sometimes children find it difficult to correctly categorise the rhythm of day and night. They wake up and think it's time to get up when they should actually stay in bed for a few more hours. This problem is often exacerbated when the days get longer and shorter or summer and winter time begin. The display is blue at night and also shows the moon. This is a sign for your child to stay in bed. Time to get up. This way you can teach any child - even if they can't set a clock yet - to stay in bed longer and give you more sleep. The sleep trainer is wireless and rechargeable.