The quality of the device is amazing. The speakers are of high quality with good detailing to the music instruments. Have the balanced bass and treble. Ergonomics of the earpiece design is excellent that it fits very well in my ears. very good product to those who can not stop listening to music at any cost. work, exercise, walk, Sleep any activity... so comfortable. Talking about battery life, you can continuously watch 2 movies (2 and half hours above each) in single charge, which means battery lasts up to 5-6 hours.