Beyerdynamic A200p Portable Mobile DAC Headphone Amp for iPhone and Android Phones, Black/Silver The core of the A200p is the Wolfson WM8740 DAC with 24 bit resolution at a sampling frequency of 96 kHz HD audio, crystal-clear sound for mobile devices and laptops Pure digital music data for playback from several type devices such as the iPhone, iPod, iPad via Lightning connector, Android smartphones tablets with Android 4.1 or higher via Micro USB, as well as Mac and Windows version laptops LED display for charging, operation and volume, 3 buttons for music playback/pause and fast forward and reverse, On off switch with locking function Integrated rechargeable battery with up to 11 hours operating time, volume control with 135 level steps Included accessories and cables: Lightning, USB, Micro-USB and leather case, extremely compact and lightweight, includes smartphone strap