6 reasons for buying1.Fort battery life, large capacity battery and intelligent energy saving algorithm provide 7 days of battery life.2.Brey oxygen monitoring, blood oxygen level monitoring. 3. Music control, connect to the Bluetooth mobile phone, easily control your list of favorite songs on your phone, accompanied by music4.Monitoring of heart rate, intelligent heart rate algorithm, rise reminder and decreased heart rate, protects Health all day long. etc., registers several sports data for you