The HA-2 is an elegant yet sophisticated <b>portable headphone amplifier</b> from <a href="http://www.selfridges.com/GB/en/cat/oppo/home-tech/" style="text-decoration: none"><font color="black"><b>Oppo</b></font></a>. With a built-in rechargeable battery, it is engineered to enhance music playback from mobile phones and portable music players. Featuring hybrid class AB amplification and a USB DAC that supports 384 kHz PCM and DSD256, the HA-2 offers high performance digital-to-analog conversion for Apple’s iPhone/iPod products, a wide range of Android devices, PC and Mac computers. The HA-2 may be conveniently used to charge mobile devices on-the-go and itself can be efficiently charged in 30 minutes.