The AK XB10 uses aptX HD technology, the latest Bluetooth codec from Qualcomm. 24-bit HD audio that was simply not possible with previous Bluetooth technologies can now be fully enjoyed with aptX HD. Along with DAC, amp, and essential components of fine audio, the AK XB10 delivers a distinctive difference in sound from conventional Bluetooth products. Qualcomm aptX HD While the AK XB10 is a device that wirelessly transmits audio data from smartphones via Bluetooth, it is quite different from conventional Bluetooth devices, in that it supports the aptX HD Bluetooth codec. Just as the display resolutions of televisions evolved from standard to high-definition to 4K ultra-HD for sharper image quality, we are now in the era in which Bluetooth now supports 24-bit audio resolution. 24-bit HD audio that was simply not possible with previous Bluetooth technologies can now be fully enjoyed with aptX HD Typically used in professional broadcasting, the original aptX audio codec is widely used for 16-bit near-CD quality sound. The benefits of the aptX codec include superior compression, low computational cost, and low transmission delay. * Devices connected to the AK XB10 must support the aptX and aptX HD codecs for 24bit audio playback. Perfect Sound Equipped with a Hi-Fi DAC capable of reproducing high-quality sound up to 24-bit/192 kHz Dual Audio Output Equipped with both 3.5mm unbalanced & 2.5mm balanced audio outputs iOS & Android Compatible Compatible with all iOS, Android, and many other Bluetooth devices Handsfree Function Supports voice calls and features a built-in microphone: receive calls when using earphones without a microphone Design Concept Inspired by Astell&Kern's principal design motif of light and shadow.