Built-in Battery: With high performance rechargeable polymer battery, this headphon e provides 8-10 hours of music time, less than 3 hours of charging time FUNCTIONAL! Durable Earphone With mic Tangle Free cables and Call Receive / Cut and Play / Pause Button (Change Track on Double and Triple Click) makes it easier to have long lasting, tangle and frustration free music and call experience. These sweat resistant earphones are great for running and gym workouts.