The breathable, fibers of hypoallergenic material allows healthy oxygen in while keeping dry air out, which make you fall asleep faster. Built-in microphone to let you won't miss any callings. The Dark Blue Bluetooth Sleep Mask with 3D Contour Design, They are very lightweight and Skin-friendly, Breathable fabric is comfortable to wear, no more bulky mask, you could hardly feel that you are wearing anything when you fall asleep.