The AK Jr Portable High Definition Music Player from Astell & Kern is a pocket-sized audio system capable of studio Mastering Quality Sound (MQS) support and playback. MQS is a high definition digital music format operating at 24 bits and sample rates from 96 to 192 kHz, which translates to distortion-free sound without data loss. MQS sources are commonly saved as a lossless 24-bit WAV or FLAC files during record production at the time of the mastering source. The AK Jr also supports 2.8 MHz DSD64 playback by converting to PCM. The AK Jr has an integrated single-channel Wolfson WM8740 DAC providing exceptional sonic quality and detail. It can also be used as an external DAC when connected to a Mac or PC via USB. The player features 64GB of internal flash memory and a microSD card slot that supports up to 64GB from a separately sold card. This allows you to store a maximum of 128GB of high definition lossless music. The 3.1" WQVGA touchscreen provides smartphone-style control over playback, while the sleek aluminum body and volume wheel provide a smooth analog feel. The built-in battery recharges via USB and lasts for up to 8 hours of playback. The AK Jr ships with a set of screen protectors and micro-USB cable. Integrated Wolfson WM8740 DAC allows the player to provide high definition quality and detail, and can be used as an external DAC for PC or Mac. Wirelessly stream music to any Bluetooth compatible device such as headphones, home hi-fi systems, and car stereos. The built-in rechargeable lithium-polymer battery has a capacity of 1450mAh and can be recharged via USB. Listen continuously for up to 8 hours on a charge. Extended frequency control with a 10 band graphic EQ in .5 dB increments. In addition, multiple user EQs are supported so that users may create custom EQs to fit each music genre and change them whenever desired.