The Andes E07K Portable USB DAC Headphone Amplifier from Fiio can be used for the playback of audio from a computer or analog source. It has both a USB input for digital audio and a 3.5mm input for analog audio sources. The Andes E07K provides you with two 3.5mm stereo headphone outputs. The Andes E07K features independent bass and treble adjustment, allowing you to customize the playback of your sound. Three levels of gain adjustment at 0, 6, and 12dB provide you with further control over the output. The unit is powered by its internal rechargeable battery, which is capable of up to 24 hours of playback on a single charge. Right and left output can be independently adjusted Supports playback of digital audio with resolutions up to 96kHz/24-bit via its USB port Hold Key prevents accidental operation changes Independent bass and treble adjustment function provides 20 shifting choices from -10dB to 10dB Lo Bypass Switch creates a line output signal for use with the Fiio E09K or L7