Featuring with bluetooth 5.0 technology, built-in adjustable HD stereo speaker and microphone, true HD HIFI sound featuring produce great sound quality, bluetooth can pair your any Smartphones Pad Tablets easily.Battery Chip is upgraded which is the best chips for sleep headphones. Built-in 200mAh high-performance battery, charge about 2-2.5 hours provide more than 8 hours playing time. IT CAN BE ADJUSTED ACCORDING TO THE SIZE OF THE HEAD. Ideal for children, college students,dorm life.