Features: The comfortable headphone can be worn by students in class, which ensures that everyone can hear the teacher clearly and improve their concentration. You can send travel headphones to your schoolmates, classmates, students, colleagues and family members, so that they can listen to something at any time. Specifications: Material: plastic, foam Color: black, gray, white Size: as pictures show Package includes: 150 x Headphone packs students Notes: Manual measurement, please allow slight errors on size. The color may exist a slight difference due to different screen displays. Winding risk may exist, adult supervision is needed when it is applied by kids.