Built-in Speakers: Bring On the Beat Wireless Music Player: Music All The Way Headphones: Listening Comfort Extra Bass Driver Unit: Step Up the Bass Wide Audio Formats: Music Knows No Boundaries Extended Battery Life: Longer Playtime - 20 hour battery life • The 3 in 1 Music Maker: • The NWZ-WH505 does more than most headphones. With an MP3 player built-into the headphones there's no need for wires, or you can play music through exterior speakers. • Wireless Headphones: Sacrifice nothing when it comes to sound detail. Extra-large 40mm neodymium driver delivers dynamic bass and a wide frequency range of 5-25,000Hz, so you hear lows and highs accurately. Want to really rock out? Just press the sound enhancement button to boost the bass, or press it twice for tight bass and clear mid-highs. • Surround-Sound Speakers With VPT Air and xLOUD Technology: Listen with friends, or simply keep your ears open to traffic on the street. In 1 touch, play music in surround sound from the outward facing speakers. • Built-in MP3 Player with ZAPPIN: Intuitive controls and music track browsing allows you to jump to the chorus section of a track. • Specifications: Speaker Driver: 40 mm Frequency Response: 5 Hz - 25,000 Hz Memory: Approx. 16 GB (4,000 Songs) Inputs/Outputs: USB microB, USB 2.0, Stereo 3.5 mm Power: 3.7V Rechargeable Battery Battery Playback: Up To 20 Hours (Headphone), 5 Hours (Speakers) Charge Time: 2 Hours (Full)