The Dreem headband monitors brain activity and movement, as well as heart and breathing frequency, during the night and emits audio signals to improve sleep quality. On the front are four EEG sensors, a pulse oximeter and two bone-conduction speakers, which direct the sound straight into the inner ear so that only the wearer hears the sounds and the sleep of their partner is not disturbed. The headband is made of foam and textile. The elastic band at the back of the head ensures an optimum fit.